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1) What it measures

Ferritin is a protein that stores iron in the body

2) Why it matters

Low ferritin means depleted iron stores, the earliest sign of iron deficiency anaemia. High ferritin can indicate iron overload, but ferritin also rises as an “acute phase” reactant during inflammation or liver injury

3) When ferritin is LOW

This always indicates low total body iron stores

Typical patterns

• Iron-deficiency anaemia: Low serum iron; High TIBC, low transferrin saturation; Seen with chronic blood loss (heavy periods, GI bleed) or insufficient dietary iron; Symptoms include fatigue, hair loss, and pica
• Long-term iron depletion without anaemia: Low ferritin with normal Hb, indicating that if uncorrected, anaemia will follow; Women of childbearing age with inadequate iron intake often show this
• Improving inflammation: As inflammation resolves, ferritin can drop revealing a true iron deficiency that was masked, e.g. in rheumatoid arthritis under treatment, ferritin might fall indicating the true iron status (typically due to chronic blood loss or poor intake)

4) When ferritin is HIGH

This indicates iron overload or simply be due to inflammation or cell damage

Typical patterns

• Hemochromatosis or iron overload: Excess iron deposition in tissues; Transferrin saturation is usually high
• Chronic inflammation: Chronic infections, cancer, or autoimmune diseases rather than iron overload
• Liver disease: Cirrhosis or hepatitis even without total body iron overload; Liver enzymes (ALT, AST) help differentiate
• Ferritinopathy: Rare conditions like hemophagocytic syndrome
• Recent blood transfusions or iron infusion: Influx of iron

5) Included in follow-up panel: No

1) What it measures

Haematocrit is the percentage of blood made up of red blood cells

2) Why it matters

Hct usually rises and falls in together with haemoglobin and helps assess blood thickness (viscosity)

3) When haematocrit is LOW

This usually mirrors anaemia or dilution of blood

Typical patterns

• Iron deficiency or chronic disease anaemia: Hb is also low; In iron deficiency MCV/MCH is often low (red cells are small/pale); In chronic disease, inflammation markers (e.g. CRP) are high
• Acute or chronic blood loss: Iron markers (e.g. ferritin) may fall over time
• Bone marrow suppression: White blood cells (WBC) and platelets may be low
• Overhydration: Excess fluids dilute the blood; Sodium may be low

4) When haematocrit is HIGH

This suggests either concentrated blood or increased red cell mass

Typical patterns

• Dehydration: Fluid loss (vomiting, diarrhoea, severe sweating); Hb increases in parallel
• Smoking or chronic hypoxia: Raised Hb and RBC count
• Polycythaemia vera: Multi-lineage increases in RBC and platelets/ WBC
• High-altitude exposure: Physiological adaptation makes body produce extra red cells to capture more oxygen

5) Included in follow-up panel: Yes (Full Blood Count)

1) What it measures

Haemoglobin is an iron-rich protein inside red blood cells that carries oxygen from the lungs to the rest of the body

2) Why it matters

Too little haemoglobin means less oxygen delivery, leading to fatigue, weakness and breathlessness. Too much haemoglobin can thicken the blood, increasing strain on the heart and raising the risk of blood clots

3) When haemoglobin is LOW

This usually reflects anaemia. The pattern of other blood markers helps identify the cause

Most common patterns

• Iron deficiency anaemia: Low ferritin (iron stores); Low MCV/MCH (small, pale red cells); Transferrin/total iron-binding capacity (TIBC) is often high
• Anaemia of chronic disease/ inflammation: Ferritin is normal or high (iron is stored but not released); C-reactive protein (CRP) is often raised; Transferrin/total iron-binding capacity (TIBC) is often low
• Chronic kidney disease: Reduced erythropoietin (kidney hormone); Creatinine and/or cystatin C is often raised
• Vitamin B12 or folate deficiency: MCV is high (large red cells); Sometimes low white blood cell (WBC)/ platelets

4) When haemoglobin is HIGH

This reflects either concentrated blood or increased red cell production (erythrocytosis)

Most common patterns

• Dehydration: High haematocrit (percentage of red cells); Sodium and urea levels may be raised
• Smoking or Chronic low oxygen (hypoxia): Raised RBC count and haematocrit; Seen in COPD or sleep apnoea
• Polycythaemia vera (bone marrow overproduction): Hb, haematocrit and RBC count are often high; Platelets and white cells may also be raised
• Testosterone therapy (anabolic steroids or erythropoietin injections): Raised Hb/haematocrit (erythrocytosis)

5) Included in follow-up panel: Yes (Full Blood Count)

1) What it measures

Serum iron is the amount of circulating iron in the blood

2) Why it matters

Too low iron leads to iron-deficiency anaemia (insufficient haemoglobin, causing fatigue and weakness). Too high can indicate iron overload which can damage organs (iron is toxic in excess, depositing in liver, heart, joints)

3) When iron is LOW

This indicates iron deficiency or poor iron availability for red cell production

Typical patterns

• Iron-deficiency anaemia: Low ferritin; High total iron-binding capacity (TIBC); Symptoms include fatigue, pale skin, and sometimes pica (cravings for non-food items); Caused by chronic blood loss (heavy periods, gastrointestinal bleeding) or insufficient dietary iron
• Anaemia of chronic disease: Normal or high ferritin (iron is stored but not released); Often low or normal transferrin and TIBC; Caused by chronic infections or inflammatory disorders
• Poor diet or malabsorption: Strict vegan diet without supplementation or celiac disease, after gastric bypass
• Acute illness: Mild and temporary
• Pregnancy: Increased demand for foetal development and increased blood volume; (Iron supplements needed)

4) When iron is HIGH

This indicates iron overload or excessive release of stored iron

Typical patterns

• Hemochromatosis: Genetic disorder; Iron build up in tissues; High transferrin saturation; Ferritin often very high; Can lead to liver disease, skin bronzing, diabetes, and heart problems if untreated
• Sideroblastic anaemia: Bone marrow disorder; Iron cannot be incorporated into haemoglobin and accumulates in cells; High ferritin
• Iron poisoning: Toxic amounts ingested; Symptoms include vomiting, abdominal pain, and can progress to shock (medical emergency)
• Multiple transfusions: Raised ferritin; (Iron chelation therapy might be required)
• Liver disease (like chronic hepatitis or cirrhosis); Raised ferritin; Release of stored iron from damaged liver cells

5) Included in follow-up panel: No

1) What it measures

MCH is the average amount of haemoglobin contained in each red blood cell

2) Why it matters

It helps classify types of anaemia. Low MCH means cells have less haemoglobin and are pale. High MCH means cells carry more haemoglobin and are more richly coloured

3) When MCH is LOW

Red cells contain less haemoglobin

Typical patterns

• Iron deficiency: Low ferritin; Low MCV and MCHC; Transferrin saturation is low while TIBC is high
• Anaemia of chronic disease: Normal or high ferritin; CRP often raised.
• Thalassemia trait: Very low MCV; RBC count is normal or high (key clue)

4) When MCH is HIGH

This usually reflects large red cells (macrocytosis)

Typical patterns

• Vitamin B₁₂ or folate deficiency: High MCV
• Alcohol excess: High MCV; GGT (liver enzyme) may be raised
• Liver disease or hypothyroidism: Macrocytosis without iron deficiency

5) Included in follow-up panel: Yes (Full Blood Count)

1) What it measures

MCHC is the concentration of haemoglobin within each red blood cell.

2) Why it matters

Distinguishes pale cells from over-dense or damaged cells

3) When MCHC is LOW

It means red cells are pale.

Typical patterns

• Iron deficiency anaemia: Low ferritin; Low MCV and MCH.
• Anaemia of chronic disease: Raised CRP; Normal ferritin despite low serum iron.
• Thalassemia trait: Very low MCV (microcytosis) but normal iron stores.

4) When MCHC is HIGH

Red cells are unusually high haemoglobin concentration or damaged.

Typical patterns

• Hereditary spherocytosis: Sphere-shaped red cells that are densely packed with Hb.
• Autoimmune haemolytic anaemia: Damaged red cells (spherocytes); High bilirubin; Often high LDH.
• Dehydration: relative increase in concentration due to low plasma volume.
• Laboratory artifact: Cold agglutinins; Requires blood smear correlation.

5) Included in follow-up panel: Yes (Full Blood Count).

1) What it measures

MCV is the average size of red blood cells

2) Why it matters

This is the primary classifier of anaemia types and should be interpreted along with iron studies, B₁₂/folate levels, thyroid and liver markers

3) When MCV is LOW

This indicates microcytic pattern: red cells are small

Typical patterns

• Iron deficiency anaemia: Low ferritin; Low transferrin saturation
• Thalassemia trait: Very low MCV; Normal ferritin; RBC count is often normal or even high
• Anaemia of chronic disease: Ferritin is normal/high; CRP is high

4) When MCV is HIGH

This indicates macrocytic pattern- red cells are large

Typical patterns

• Vitamin B₁₂ or folate deficiency: can cause megaloblastic anaemia with possible low platelets or neutrophils; Often with neurological or mucosal symptoms
• Alcohol excess: GGT liver enzyme may be raised
• Liver disease: Macrocytosis without vitamin (folate) deficiency
• Hypothyroidism: Underactive thyroid; Check TSH and free T4

5) Included in follow-up panel: Yes (Full Blood Count)

1) What it measures

Platelet count is the number cell fragments that help blood clot and stop bleeding

2) Why it matters

Too few platelets (thrombocytopenia) can lead to easy bruising or serious bleeding, since clots cannot form effectively. Too many platelets (thrombocytosis) can make blood prone to abnormal clotting (thrombosis) and, sometimes bleeding issues if platelet function is abnormal

3) When platelet count is LOW

This indicates thrombocytopenia: increased bleeding risk if severe

Typical patterns

• Immune thrombocytopenia (ITP): Antibodies destroy platelets; Bruising or petechiae; Often follows a viral illness
• Bone marrow disorders: Aplastic anaemia, leukaemia, or bone marrow metastases; Other blood counts (RBCs, WBCs) are often low; Bone marrow biopsy helps identify these causes
• Drug-induced thrombocytopenia: Certain medications (e.g. heparin, quinine, some antibiotics and anti-seizure drugs); Immune destruction or marrow suppression; Heparin-induced thrombocytopenia (HIT) increases clot risk.
• Splenic sequestration: Enlarged spleen (e.g. due to cirrhosis) can trap platelets, though production may be normal
• DIC or TTP: Disseminated intravascular coagulation and thrombotic thrombocytopenic purpura; Signs of clotting and bleeding may appear.

4) When platelet count is HIGH

This indicates thrombocytosis: increased risk of abnormal clotting

Typical patterns

• Reactive (secondary) thrombocytosis: Common triggers: recent surgery or trauma, acute blood loss, severe infection, chronic inflammation, or iron deficiency anaemia
• Essential thrombocythemia: Bone marrow disorder where the megakaryocytes overproduce platelets; Can cause clotting complications (like thromboses in unusual sites) or paradoxical bleeding
• Post-splenectomy: Spleen is no longer there to store and eliminate platelets; Can be long-term
• Chronic inflammation or infection: Conditions such as tuberculosis or rheumatoid arthritis; Acute-phase reactant response
• Cancer-associated: Inflammatory cytokines or marrow involvement

5) Included in follow-up panel: Yes (Full Blood Count)

1) What it measures

RBC count is the number of red blood cells in a volume of blood

2) Why it matters

Low RBC count (anaemia) means reduced oxygen delivery to organs, causing fatigue and pallor. High RBC count (erythrocytosis) thickens the blood and can increase the risk of clots or stroke

3) When RBC count is LOW

This causes anaemia and can result from decreased production, increased destruction, or loss of RBCs

Typical patterns

• Nutritional anaemia: Iron deficiency shows low ferritin and often microcytosis; B₁₂/folate deficiency shows macrocytosis; Often accompanied by fatigue and shortness of breath.
• Bone marrow disorders: Aplastic anaemia or myelodysplastic syndromes; RBC, WBC, and platelets may all be low; Bone marrow biopsy helps confirm.
• Chronic kidney disease: Low erythropoietin; Often creatinine is high and there may be other signs of uraemia.
• Chronic illness/inflammation: Normal/high ferritin; Low serum iron; Underlying diseases (e.g. rheumatoid arthritis or chronic infection)
• Haemolysis or blood loss: High bilirubin or positive faecal occult blood depending on cause.

4) When RBC count is HIGH

This causes erythrocytosis or polycythaemia, blood can become more viscous.

Typical patterns

• Polycythaemia vera: Hb, and haematocrit are significantly raised; Often WBCs and platelets are high.
• Chronic hypoxia: High haematocrit; Causes include chronic lung diseases (COPD, emphysema), living at high altitude, or heavy smoking.
• Dehydration: Low plasma volume (from severe diarrhoea, vomiting, or diuretic use)
• Erythropoietin (EPO) excess: Exogenous EPO use (doping) or EPO-producing tumours; Use of anabolic steroid or testosterone
• Metabolic syndrome/High insulin: Insulin resistance and obesity; Often accompanied by inflammation markers

5) Included in follow-up panel: Yes (Full Blood Count)

1) What it measures

The WBC count is the total number of immune cells that fight infection and respond to inflammation

2) Why it matters

It reflects immune system activity. High WBC (leucocytosis) often signals infection or inflammation in the body. Low WBC (leukopenia) can indicate bone marrow problems, severe infection, or immune suppression

3) When WBC count is LOW

This indicates leukopenia: the immune cell count is low and can leave a person prone to infections

Typical patterns

• Bone marrow failure or suppression: Can be due to aplastic anaemia, chemotherapy, radiation, or marrow infiltration by tumour; Often other cell lines (RBC, platelets) are low too
• Severe infections (sepsis): Certain viral infections (e.g. dengue or hepatitis) and some severe bacterial infections can cause leukopenia
• Autoimmune disorders: Diseases (e.g. lupus) can cause the immune system to attack WBCs or bone marrow; Medications for autoimmune disease (immunosuppressants) can also lower WBC
• Medication or toxin effect: Certain drugs (some antibiotics, anticonvulsants, chemotherapy) and chemical exposures (e.g. benzene, arsenic) can damage marrow or destroy WBCs
• Viral illnesses: Many viral infections lower neutrophils. Infectious mononucleosis, HIV, and hepatitis can all cause a low WBC count during the acute phase

4) When WBC count is HIGH

This indicates leucocytosis: an active response to a trigger.

Typical patterns

• Infection: Increase in neutrophils; Pneumonia or appendicitis often show leucocytosis
• Inflammation: Rheumatoid arthritis, inflammatory bowel; Allergic reactions or asthma can raise eosinophils
• Leukaemia or blood cancers: Cells are often immature or abnormal (blasts)
• Stress or steroid medication: Severe physical stress (trauma, surgery) or high-dose corticosteroids; Usually transient
• Tissue damage: Inflammatory response; Post-splenectomy (removal of spleen; spleen normally helps clear out old white cells)

5) Included in follow-up panel: Yes (Full Blood Count)

1) What it measures

Folate is a B-vitamin needed for DNA synthesis and red blood cell production. It’s especially important for rapidly dividing cells and during pregnancy for foetal development

2) Why it matters

Folate deficiency leads to megaloblastic anaemia with symptoms like fatigue and mouth sores. In pregnancy, low folate increases the risk of neural tube birth defects in the baby. Excess folic acid intake is generally not harmful, but very high supplemental doses can mask a B₁₂ deficiency

3) When folate is LOW

This causes folate-deficiency anaemia and can elevate homocysteine levels (a risk factor for cardiovascular disease)

Typical patterns:

• Poor diet: Inadequate intake of leafy vegetables or fortified foods; Can occur in malnutrition or in people with very limited diets
• Malabsorption: Diseases affecting the upper small intestine (where folate is absorbed) can cause deficiency; (celiac disease or surgical removal of parts of the intestine)
• Excessive alcohol use: Alcohol interferes with folate absorption and increases excretion
• Increased requirements: Pregnancy greatly increases folate needs (for foetal growth); Chronic haemolytic anaemia (rapid turnover of RBCs uses up folate)
• Medications: Certain drugs (e.g., methotrexate, some anti-seizure medications, or trimethoprim antibiotic) interfere with folate metabolism and can induce folate deficiency

4) When folate is HIGH

This usually reflects supplementation or a folate-rich diet

5) Included in follow-up panel: No

1) What it measures

Total iron-binding capacity (TIBC) measures the blood’s capacity to bind iron with transferrin. It reflects the amount of transferrin available

2) Why it matters

It rises when body iron is low and falls when body iron is high or during inflammation. TIBC helps differentiate iron deficiency (high TIBC) from anaemia of chronic disease or hemochromatosis (low TIBC)

3) When TIBC is HIGH

This indicates increased transferrin levels

Typical patterns:

• Iron deficiency anaemia: Serum iron is low and transferrin saturation is low; Ferritin is low
• Pregnancy or oestrogen therapy: Increase transferrin production, leading to higher TIBC; This can lower TSAT
• Early iron depletion: High TIBC as an early indicator of iron deficiency
• Acute hepatitis: Liver injury can transiently increase certain proteins; TIBC may rise in some acute liver inflammations; Ferritin usually also rises due to inflammation

4) When TIBC is LOW

This means reduced transferrin or fewer available iron-binding sites

Typical patterns:

• Hemochromatosis: TIBC is low or low-normal, and transferrin saturation is very high
• Chronic inflammation (anaemia of chronic disease): Ferritin is normal or high (iron is stored but not released), and serum iron is low, resulting in a low TSAT
• Malnutrition or liver disease: Poor protein intake or liver failure can lead to low transferrin production; Nephrotic syndrome (protein loss in urine) can also lower transferrin levels

5) Included in follow-up panel: No

1) What it measures

Transferrin is a protein in the blood that binds and transports iron. It is produced by the liver

2) Why it matters

Measuring transferrin (or its equivalent Total Iron Binding Capacity, TIBC) helps assess iron metabolism. High transferrin usually indicates iron deficiency (the body trying to capture more iron). Low transferrin can indicate iron overload or an inflammatory state (transferrin is a negative acute phase reactant)

3) When transferrin is LOW

This suggests either iron overload or suppression of transferrin production (as in inflammation or malnutrition)

Most common patterns:

• Hemochromatosis: In hereditary iron overload, transferrin levels are low due to feedback suppression (body reduces iron transport capacity)
• Chronic illness/inflammation: Transferrin is a negative acute phase reactant, so inflammation or chronic disease (infection, cancer) lowers transferrin levels
• Protein malnutrition or liver disease: Poor protein intake or liver dysfunction leads to reduced transferrin synthesis

4) When transferrin is HIGH

This indicates that the body is trying to mobilise or bind more iron, typically due to iron deficiency or increased demand

Most common patterns:

• Iron deficiency anaemia: Low body iron causes the liver to increase transferrin production to scavenge more iron, so transferrin (or TIBC) is elevated
• Pregnancy or oestrogen therapy: Oestrogen can increase transferrin levels (e.g., during pregnancy or with oral contraceptives), elevating transferrin beyond normal

5) Included in follow-up test: No

1) What it measures

Transferrin saturation (TSAT) is the percentage of the iron-transport protein transferrin that is bound by iron

2) Why it matters

Low TSAT means insufficient available iron relative to transferrin (common in iron deficiency). High TSAT suggests iron overload or low transferrin binding capacity

3) When TSAT is LOW

This means a large portion of transferrin is empty, indicating iron supply is low relative to demand

Most common patterns:

• Iron deficiency: Very low TSAT with low serum iron and high TIBC, confirming true iron deficiency if ferritin is also low; Fatigue, hair loss, and brittle nails may be present
• Anaemia of chronic disease: TSAT is low because serum iron is trapped in storage; Transferrin (TIBC) is normal or low; Ferritin is normal or high, distinguishing it from pure iron deficiency
• Pregnancy (late stage): Transferrin production increases, which can lower TSAT if iron intake isn’t raised

4) When TSAT is HIGH

This means transferrin is highly loaded with iron

Typical patterns:

• Hemochromatosis: Very high TSAT is a hallmark of hereditary hemochromatosis (iron overload); Ferritin will also be high
• Recent iron intake or transfusion: Immediately after high-dose iron or multiple blood transfusions, serum iron can spike, making TSAT temporarily high
• Iron poisoning: In acute iron overdose, serum iron becomes extremely high, and transferrin can saturate near 100%, leading to free toxic iron
• Ineffective erythropoiesis: In conditions like aplastic anaemia or certain bone marrow disorders, iron isn’t used for red cell production, so TSAT can be high despite anaemia (iron remains in plasma)
• Advanced liver disease: Low transferrin production in severe liver disease can raise TSAT because TIBC is low, even without true iron overload

5) Included in follow-up panel: No

1) What it measures

Vitamin B₁₂ level in blood reflects the availability of this B-vitamin, which is essential for red blood cell formation, DNA synthesis, and nerve function

2) Why it matters

Low B₁₂ can cause anaemia (leading to fatigue, weakness, pallor) and neurological symptoms (numbness, balance problems, memory issues), which can become irreversible if prolonged. High B₁₂ is usually due to supplementation or, rarely, liver disease or certain leukemias

3) When B₁₂ is LOW

This indicates deficiency, typically from poor absorption or inadequate intake

Typical patterns:

• Pernicious anaemia: Severe B₁₂ deficiency with high MCV anaemia and often neurologic symptoms
• Malabsorption from GI disease: Chronic atrophic gastritis (e.g., due to H. pylori) or surgical removal of part of the stomach/ileum (gastric bypass); Diseases like Crohn’s or celiac affecting the small intestine can also lead to B₁₂ deficiency
• Dietary deficiency: Strict vegans who consume no animal products are at risk, since B₁₂ is naturally found only in animal-derived foods
• Other causes: Chronic alcoholism can reduce B₁₂ absorption and intake

4) When B₁₂ is HIGH

This is usually due to supplementation or, rarely, liver disease or certain leukemias

Typical patterns:

• Supplementation: Raised B₁₂ blood levels above normal (generally harmless)
• Liver disease: In acute hepatitis or liver cirrhosis, stored B₁₂ can leak out of liver into the bloodstream, causing an elevated level
• Myeloproliferative disorders: Certain blood cancers (like chronic myeloid leukaemia or polycythaemia vera) can raise B₁₂ levels due to overproduction of B₁₂-binding proteins

5) Included in follow-up panel: No

1) What it measures

Apolipoprotein A-I is the major protein component of HDL particles. The Apo A-I level reflects the capacity for HDL formation and function. It often correlates with HDL cholesterol levels

2) Why it matters

Apo A-I plays a key role in reverse cholesterol transport (moving cholesterol out of arteries). High Apo A-I (and HDL) generally indicates better removal of cholesterol and lower cardiovascular risk. Low Apo A-I is associated with low HDL and higher risk of coronary artery disease

3) When Apo A-I is LOW

Low Apo A-I usually corresponds to low HDL cholesterol

Typical patterns:

• Inherited low HDL disorders: Conditions like familial hypoalphalipoproteinemia or Tangier disease result in very low Apo A-I and HDL; May develop premature cardiovascular disease
• Metabolic syndrome & lifestyle factors: Insulin resistance, smoking, and diets high in refined carbs can lower Apo A-I/HDL levels as part of low “good” cholesterol
• Inflammation: Low HDL and Apo A-I

4) When Apo A-I is HIGH

High Apo A-I generally means high HDL levels

Typical patterns:

• Genetics: Some people inherit higher Apo A-I and HDL levels, which is usually protective against heart disease
• Oestrogen effect: Women tend to have higher Apo A-I than men (due to higher HDL); Oestrogen or certain medications (niacin) can raise Apo A-I modestly
• Exercise: Regular endurance exercise can increase Apo A-I/HDL levels slightly

5) Included in follow-up panel: No

1) What it measures

Apolipoprotein B is the primary protein found in atherogenic lipoproteins such as LDL, VLDL, and IDL. The Apo B level indicates the number of “bad” lipoprotein particles in the blood

2) Why it matters

Apo B is a strong indicator of cardiovascular risk because it directly measures the concentration of cholesterol-bearing particles that can penetrate arteries. High Apo B means more atherogenic particles and higher heart disease risk. Low Apo B (aside from rare genetic cases) means fewer LDL particles and lower risk

3) When Apo B is LOW

Low Apo B usually corresponds to low LDL/VLDL particle count

Typical patterns:

• Effective lipid-lowering therapy: Treatments that greatly reduce LDL (statins, PCSK9 inhibitors) will lower Apo B
• Genetic abetalipoproteinemia: An extremely rare condition where Apo B is almost absent leads to very low cholesterol levels; Causes fat absorption problems
• Malnutrition or hyperthyroidism: Severe malnutrition or overactive thyroid can lower lipoprotein levels, hence Apo B

4) When Apo B is HIGH

High Apo B indicates an increased number of atherogenic lipoprotein particles

Typical patterns:

• Familial combined hyperlipidaemia: Common genetic disorder where individuals have elevated Apo B and often moderately high LDL and triglycerides; This increases cardiovascular risk
• Familial hypercholesterolemia: Very high LDL from genetic causes will result in high Apo B levels
• Metabolic syndrome/Type 2 diabetes: High triglycerides and low HDL often correlate with elevated Apo B
• Hypothyroidism: Underactive thyroid can increase LDL particle number, elevating Apo B

5) Included in follow-up panel: No

1) What it measures

Apo C-II is a small protein carried on triglyceride-rich lipoproteins. It acts as a co-factor for lipoprotein lipase, the enzyme that breaks down triglycerides in the blood.

2) Why it matters

Apo C-II is essential for the normal clearance of triglyceride-rich particles. If Apo C-II is deficient or nonfunctional, triglycerides cannot be properly broken down, leading to severe hypertriglyceridemia and risk of pancreatitis

3) When Apo C-II is LOW

Low or absent Apo C-II impairs triglyceride metabolism

Typical patterns:

• Familial Apo C-II deficiency: A very rare hereditary condition in which Apo C-II is lacking or nonfunctional; Presents in childhood or young adulthood with extremely high triglycerides and recurrent pancreatitis; Patients may have eruptive xanthomas (yellowish skin bumps) and “milky” plasma due to chylomicrons

4) When Apo C-II is HIGH

This is commonly not associated with a specific direct pathology. It may rise secondarily when triglyceride-rich lipoproteins are high

Typical patterns:

• Secondary to hypertriglyceridemia: In conditions with high VLDL/chylomicrons (like obesity, metabolic syndrome), Apo C-II may be carried in greater total amount simply because there are more triglyceride-rich particles

5) Included in follow-up panel: No

1) What it measures

Apo C-III is a small apolipoprotein found on chylomicrons, VLDL, and HDL. It inhibits lipoprotein lipase and hepatic uptake of triglyceride-rich particles

2) Why it matters

Apo C-III slows the clearance of triglyceride-rich lipoproteins. High Apo C-III levels are associated with increased triglycerides and may promote atherosclerosis. Low Apo C-III is generally associated with lower triglyceride levels and possibly reduced cardiovascular risk

3) When Apo C-III is LOW

Low Apo C-III would facilitate faster triglyceride clearance

Typical patterns:

• Genetic variant (Apo C-III loss-of-function): Genetic mutations that reduce Apo C-III function lead to lower triglycerides and lower risk of heart disease; This is generally beneficial and asymptomatic

4) When Apo C-III is HIGH

High Apo C-III can contribute to hypertriglyceridemia and may be pro-atherogenic

Typical patterns:

• Familial hypertriglyceridemia: Genetic or combined causes of high triglycerides lead to elevated Apo C-III levels, which further impede triglyceride breakdown
• Metabolic syndrome/Type 2 diabetes: Elevated Apo C-III as part of the dysregulation of lipid metabolism, correlating with high triglycerides
• Kidney disease: Chronic kidney disease can lead to higher Apo C-III and triglyceride levels due to altered metabolism

5) Included in follow-up panel: No

1) What it measures

HDL cholesterol is the amount of cholesterol carried by high-density lipoproteins (“good” cholesterol). HDL particles help remove excess cholesterol from arteries and transport it to the liver for disposal

2) Why it matters

High HDL levels are associated with lower risk of heart disease (HDL is protective). Low HDL is associated with higher risk of coronary artery disease

3) When HDL is LOW

This is a risk factor for cardiovascular disease, as there is less “good” cholesterol scavenging

Typical patterns:

• Metabolic syndrome & Type 2 diabetes: Low HDL along with high triglycerides and central obesity; Insulin resistance lowers HDL levels
• Poor diet & inactivity: Diets high in refined carbs and trans fats, along with sedentary lifestyle and smoking, tend to depress HDL levels
• Smoking: Cigarette smoking is known to reduce HDL
• Genetic disorders: Rare familial conditions (e.g., Tangier disease) cause extremely low HDL and premature artery disease

4) When HDL is HIGH

This is generally considered protective against heart disease.

Typical patterns:

• Exercise and moderate alcohol: Regular aerobic exercise and moderate alcohol intake can raise HDL modestly
• Genetics: Some individuals inherit very high HDL levels; In most cases this is beneficial; Exceedingly high HDL in certain genetic variants may be less effective
• Oestrogen effect: Premenopausal women often have higher HDL partly due to oestrogen; Hormone replacement therapy can also raise HDL

5) Included in follow-up panel: Yes

1) What it measures

LDL cholesterol is the amount of cholesterol carried by low-density lipoproteins (“bad” cholesterol) in the blood. LDL transports cholesterol to tissues, and excess LDL tends to deposit cholesterol in artery walls

2) Why it matters

LDL cholesterol is the primary target for cardiovascular risk reduction. High LDL promotes plaque formation in arteries, increasing heart attack and stroke risk. Low LDL (through diet, lifestyle, or medication) significantly reduces cardiovascular events

3) When LDL is LOW

This is generally favourable for cardiovascular health. Extremely low LDL (which can occur with potent therapy or in rare genetic conditions) typically has no direct symptoms, though it may be a marker of underlying illness if not due to treatment

Typical patterns:

• Effective therapy or lifestyle: Individuals on statins, PCSK9 inhibitors, or very healthy lifestyles have low LDL; This is associated with reduced heart risk
• Underlying illness: Could be seen in severe chronic illness, hyperthyroidism, or malnutrition; Low LDL is more a consequence of illness rather than a problem itself
• Genetic hypo-beta lipoproteinemia: Rare genetic disorders cause life-long very low LDL levels; Fat absorption issues but protective from atherosclerosis

4) When LDL is HIGH

This is a major risk factor for atherosclerosis

Typical patterns:

• Familial hypercholesterolemia (FH): Genetic defects in LDL receptors or Apo B cause extremely high LDL from childhood; Patients often develop premature coronary artery disease and may have signs like tendon xanthomas
• Poor diet and lifestyle: Diets high in saturated/trans fats and cholesterol, combined with obesity and lack of exercise; Many individuals with high LDL have a mix of genetic predisposition and lifestyle factors
• Hypothyroidism: An underactive thyroid slows LDL clearance, leading to elevated LDL
• Nephrotic syndrome: This kidney condition raises LDL (and often lipoprotein(a) and triglycerides) due to increased hepatic lipoprotein production in response to protein loss
• Cholestatic liver disease: Conditions like primary biliary cholangitis can raise LDL

5) Included in follow-up panel: Yes

1) What it measures

Lipoprotein(a) is an LDL-like particle with an added protein called apolipoprotein(a) attached. The blood test measures the concentration of Lp(a). Lp(a) levels are largely genetically determined

2) Why it matters

High Lp(a) is a genetically inherited risk factor for atherosclerosis. Lp(a) can contribute to plaque buildup and is associated with increased risk of premature coronary artery disease and stroke. It also may promote blood clot formation

3) When Lp(a) is LOW

Low Lp(a) is normal for most people and indicates absence of this particular risk factor. There are no symptoms or issues caused by low Lp(a)

4) When Lp(a) is HIGH

High Lp(a) is considered a significant independent risk factor for cardiovascular disease

Typical patterns:

• Familial (genetic) elevation: May develop premature atherosclerosis even if other lipids are normal. Lp(a) can also worsen risk in those who already have high LDL
• No significant secondary causes: Lp(a) is not much affected by lifestyle. It can be mildly elevated in some inflammatory states, but in general a high level is genetic

5) Included in follow-up panel: No

1) What it measures

Small LDL-C refers to the cholesterol content carried by small, dense LDL particles

2) Why it matters

Small, dense LDL particles are considered more atherogenic (more easily penetrating artery walls and prone to oxidation) than larger, buoyant LDL. A predominance of small LDL is associated with higher risk of cardiovascular disease, often occurring in insulin-resistant conditions

3) When small LDL is LOW

A low level or proportion of small dense LDL is favourable

Typical patterns:

• Pattern A LDL: LDL particles are mostly large and buoyant which is associated with lower cardiovascular risk. It is often seen in individuals with healthy metabolic profiles (normal triglycerides, higher HDL)

4) When small LDL is HIGH

This indicates an unfavourable lipid pattern

Typical patterns:

• Metabolic syndrome/Type 2 diabetes: High triglycerides and low HDL often correlate with many small LDL particles. Insulin resistance leads to the exchange of triglycerides into LDL, making them smaller and denser
• Familial combined hyperlipidaemia: A common genetic lipid disorder where individuals have increased small dense LDL along with elevated Apo B
• High-carb diets: Diets very high in refined carbohydrates can promote small LDL formation even if total LDL is not extremely high
• Smoking and inflammation: Can shift LDL to a denser profile

5) Included in follow-up panel: No

1) What it measures

Total cholesterol is the sum of all cholesterol in the blood, including low-density lipoprotein (LDL), high-density lipoprotein (HDL), and very-low-density lipoproteins (VLDL). It provides a general measure of blood lipid levels related to cardiovascular health

2) Why it matters

Cholesterol is essential for cell membranes and hormone production, but excess cholesterol (particularly LDL) contributes to atherosclerosis (plaque buildup in arteries). High total cholesterol (hypercholesterolemia) is a major risk factor for heart disease and stroke. Very low cholesterol levels may signal underlying illness or malnutrition

3) When total cholesterol is LOW

Low cholesterol is not usually a target of treatment but may accompany certain conditions

Typical patterns:

• Hyperthyroidism: Low LDL and total cholesterol, which is generally beneficial and reverses with treatment
• Severe illness or malnutrition: Chronic diseases (advanced cancer, chronic infection) or states of malnutrition/cachexia can be associated with low cholesterol levels, as the body’s production and intake are reduced
• Liver failure: In end-stage liver disease (cirrhosis or acute liver failure), the liver cannot synthesise normal amounts of cholesterol, so blood cholesterol can be abnormally low
• Genetic hypo-beta lipoproteinemia: Rare genetic conditions result in very low LDL cholesterol from birth; Very low total cholesterol; Often asymptomatic aside from fat absorption issues

4) When total cholesterol is HIGH

This increases the risk of atherosclerosis and cardiovascular disease

Typical patterns:

• Familial hypercholesterolemia (FH): A genetic disorder causing very high LDL from a young age; Patients may develop tendon xanthomas (cholesterol deposits) and premature heart disease
• Diet and lifestyle: A diet high in saturated and trans fats (red meat, full-fat dairy, fried foods) and lack of exercise raise LDL and total cholesterol; Obesity and sedentary lifestyle further contribute
• Hypothyroidism: An underactive thyroid is a cause of elevated cholesterol; Reduced thyroid function slows cholesterol metabolism, leading to high LDL and total cholesterol
• Nephrotic syndrome: Kidney condition causes heavy protein loss in urine and triggers the liver to produce more proteins and lipids; Total cholesterol and triglycerides can become very high
• Cholestatic liver disease: Conditions that block bile excretion can markedly raise cholesterol (including abnormal lipoproteins)

5) Included in follow-up panel: Yes

1) What it measures

Triglycerides are a type of fat (lipid) in the blood, they come from the diet and are also made in the liver, stored in fat tissue and used for energy between meals

2) Why it matters

Elevated triglycerides (hypertriglyceridemia) are associated with an increased risk of cardiovascular disease and, when very high, pancreatitis. Low triglyceride levels are usually a sign of a healthy diet and are not harmful.

3) When triglycerides are LOW

This may reflect a low-fat diet, good metabolic health, or certain medications and typically pose no problem

Typical patterns:

• Healthy lifestyle: Healthy diets (low sugar/low fat) or certain medications (fibrates, omega-3 supplements) often lead to low triglycerides, which is generally beneficial
• Malabsorption or malnutrition: Inability to absorb nutrients (as in certain GI disorders) or very poor intake can lead to low triglyceride levels due to lack of dietary fat

4) When triglycerides are HIGH

This can range from mild to extreme and have different implications

Typical patterns:

• Poor diet and obesity: A diet high in sugars, refined carbs, and alcohol, combined with overweight/obesity; Often occurs alongside low HDL and is part of the metabolic syndrome
• Uncontrolled diabetes: Insulin resistance or poorly controlled diabetes mellitus; Excess glucose is converted to triglycerides in the liver
• Genetic hypertriglyceridemia: Familial disorders (e.g., familial combined hyperlipidaemia or familial chylomicronaemia); Can lead to pancreatitis
• Alcohol excess: Regular heavy alcohol use can significantly raise triglycerides
• Kidney disease or medications: Chronic kidney disease and certain drugs (like beta blockers, retinoids, oestrogen) can elevate triglycerides

5) Included in follow-up panel: Yes

1) What it measures

Creatine kinase (CK) is an enzyme found mainly in skeletal muscle, heart muscle, and the brain. CK is released into the bloodstream when muscle cells are damaged or stressed

2) Why it matters

Elevated CK is a marker of muscle injury, whether from intense exercise, muscle trauma, or diseases that damage muscle. Very high CK levels can indicate rhabdomyolysis (massive muscle breakdown), which can lead to kidney failure if untreated. Low CK is not usually significant

3) When CK is LOW

Low CK levels are generally not clinically worrisome and have no specific pathology

Typical patterns:

• Low muscle mass or inactivity: Individuals with very little muscle (e.g., frail elderly or sedentary) may have naturally lower CK levels due to less muscle enzyme present
• Hyperthyroidism: An overactive thyroid can sometimes result in slightly lower CK because of increased metabolism preventing buildup of muscle enzymes
• Late-stage muscle disease: In certain muscular dystrophies, CK can be extremely high in early active disease and then fall to low or normal in late stages when most muscle has been lost

4) When CK is HIGH

This signals muscle fibre damage or stress

Typical patterns:

• Rhabdomyolysis: Massive muscle breakdown leads to very high CK; Causes include severe trauma, prolonged immobilisation, extreme exercise, seizures, or certain drugs/toxins; Rhabdomyolysis can cause dark “tea-coloured” urine (myoglobinuria) and acute kidney injury
• Myocardial infarction: A heart attack can raise CK
• Polymyositis/Dermatomyositis: Inflammatory muscle diseases often feature CK elevations in the thousands; Symptoms include muscle weakness
• Hypothyroidism: An underactive thyroid commonly leads to moderately elevated CK due to muscle fibre sluggishness and slight injury
• Intense exercise or muscle injury: Strenuous exercise or significant muscle bruising can raise CK temporarily; This typically resolves in days
• Medications (statins): Cholesterol-lowering statin drugs can cause mild CK elevation and rarely severe CK rise in statin-induced myopathy or rhabdomyolysis

5) Included in follow-up panel: Yes

1) What it measures

High-sensitivity C-reactive protein (hs-CRP) measures very low levels of C-reactive protein in the blood. CRP is a protein produced by the liver in response to inflammation

2) Why it matters

hsCRP is used as a marker of systemic inflammation and an independent predictor of cardiovascular risk. Higher hsCRP levels correlate with higher risk of heart attacks and strokes, as ongoing inflammation can contribute to atherosclerotic plaque instability. It’s also a general marker that can indicate inflammation from various sources (infection, autoimmune disease, etc.). Low hsCRP suggests a low level of chronic inflammation

3) When hsCRP is LOW

This indicates minimal systemic inflammation

Typical patterns:

• Healthy lifestyle: Individuals who exercise regularly, eat an anti-inflammatory diet, maintain a healthy weight, and don’t smoke often have low baseline CRP levels
• Certain medications: Statins not only lower cholesterol but also can lower CRP modestly, as can anti-inflammatory drugs

4) When hsCRP is HIGH

This suggests significant inflammation

Typical patterns:

• Cardiovascular risk: Can signal higher risk for heart attack or stroke in otherwise healthy individuals
• Chronic infections or periodontal disease: Ongoing infections (e.g., gum disease) can raise CRP chronically
• Obesity and metabolic syndrome: Adipose tissue produces inflammatory cytokines; Overweight individuals often have higher CRP indicating low-grade inflammation
• Autoimmune diseases: Rheumatoid arthritis, lupus, or other chronic inflammatory diseases typically elevate CRP during active phases
• Others: CRP can also be elevated in certain cancers or after trauma, but hsCRP is usually used for subtle chronic inflammation rather than acute changes

5) Included in follow-up panel: Yes

1) What it measures

C-peptide is a short peptide that is released in equal amounts when the pancreas produces insulin

2) Why it matters

C-peptide reflects pancreatic beta-cell function. A high C-peptide indicates high insulin production (as seen in insulin-resistant states or insulin-producing tumours). A low C-peptide indicates little insulin production (as in type 1 diabetes or late-stage type 2). It is also used to differentiate types of diabetes and causes of hypoglycaemia

3) When C-Peptide is LOW

This means the pancreas is producing little or no insulin

Typical patterns:

• Type 1 diabetes: Autoimmune destruction of beta cells; Low or zero C-peptide confirms a lack of insulin
• Advanced type 2 diabetes: In late stage, the overworked beta cells “burn out,” and C-peptide that was once high may fall to low or normal despite high glucose
• Exogenous insulin administration: Blood insulin might be high, but C-peptide will be low (because their pancreas isn’t making the insulin); This can be seen in factitious hypoglycaemia
• Pancreatectomy or pancreatic damage: Surgical removal of the pancreas or destruction from chronic pancreatitis will result in low C-peptide due to loss of insulin-producing cells

4) When C-Peptide is HIGH

This indicates a high level of insulin secretion by the body

Typical patterns:

• Early type 2 diabetes/Insulin resistance: The pancreas produces excess insulin to compensate for insulin resistance; High C-peptide with normal or slightly high glucose
• Insulinoma: A beta-cell tumour causes unregulated insulin release; Insulin and C-peptide are both inappropriately high
• Sulfonylurea use: Diabetes medications that stimulate the pancreas; Excess use can cause hypoglycaemia with high insulin and high C-peptide
• Chronic kidney disease: In advanced renal failure, C-peptide can accumulate, leading to higher levels for a given insulin production rate
• PCOS/Insulin resistance states: Elevated C-peptide (and insulin) as the pancreas works harder to control blood sugar

5) Included in follow-up panel: No

1) What it measures

Blood glucose is the concentration of sugar (glucose) in the bloodstream. It reflects how well the body regulates blood sugar via insulin and other hormones

2) Why it matters

Glucose is the main energy source for the body’s cells. The body tightly controls blood sugar levels. High blood glucose (hyperglycaemia) can indicate diabetes or stress responses; chronically elevated glucose leads to complications like damage to eyes, kidneys, nerves, and blood vessels. Low blood glucose (hypoglycaemia) can cause acute symptoms such as sweating, confusion, dizziness, and even coma in severe cases

3) When blood glucose is LOW

This leads to hypoglycaemia

Typical patterns:

• Insulinoma: A rare pancreatic tumour that secretes insulin inappropriately. It causes episodes of low blood sugar, especially during fasting or exercise. Symptoms include tremors, sweating, confusion, which improve quickly after eating. This causes high insulin levels with low glucose.
• Medication-induced: Diabetic patients taking too much insulin or sulfonylurea medication can experience hypoglycaemia
• Addison’s disease (adrenal insufficiency): Lack of cortisol can impair the liver’s ability to raise blood sugar, leading to fasting hypoglycaemia in some cases (usually alongside fatigue, low blood pressure)
• Severe liver disease: The liver is responsible for releasing glucose during fasting. In acute liver failure or end-stage cirrhosis, blood sugar regulation can falter, occasionally causing low glucose

4) When blood glucose is HIGH

This leads to hyperglycaemia

Typical patterns:

• Type 2 diabetes: Typically develops gradually with insulin resistance. Patients may have increased thirst, frequent urination, fatigue, and blurred vision
• Prediabetes: Slightly elevated post-meal glucose (impaired glucose tolerance); not yet in diabetic range but higher than normal, indicating risk for developing diabetes
• Metabolic syndrome: Often includes elevated fasting glucose along with high triglycerides, low HDL, high blood pressure, and central obesity
• Type 1 diabetes: An autoimmune destruction of pancreatic cells leading to little or no insulin. Causes high glucose along with symptoms like weight loss, excessive thirst and urination
• Cushing’s syndrome: Excess cortisol (from medication or adrenal/pituitary tumours) raises blood sugar by opposing insulin. People with Cushing’s often develop glucose intolerance or diabetes
• Stress hyperglycaemia: Acute illness, severe stress, or infections can temporarily raise blood sugar in non-diabetics. For example, a heart attack or stroke may cause transient high glucose levels

5) Included in follow-up panel: Yes

1) What it measures

Haemoglobin A1c is a form of haemoglobin with glucose attached (glycated haemoglobin). The HbA1c test measures the percentage of haemoglobin that is glycosylated. This reflects the average blood glucose level over the past 2–3 months

2) Why it matters

HbA1c is used to diagnose diabetes and monitor long-term glucose control in diabetics. Higher A1c corresponds to higher average blood sugar. Very high A1c indicates chronic hyperglycaemia. Very low A1c could indicate frequent hypoglycaemia or may be seen in certain anaemia conditions, but generally low is good as long as not due to excessive medication

3) When HbA1c is LOW

This could indicate frequent hypoglycaemia or may be seen in certain anaemia conditions but generally reflects excellent blood sugar control

Typical patterns:

• Excessive diabetic therapy: In diabetic patients, an HbA1c well below target might suggest frequent hypoglycaemia from overtreatment
• Haemolytic anaemia or blood loss: Conditions that shorten red blood cell lifespan (haemolysis, significant blood loss, or transfusions) can artificially lower A1c because RBCs don’t exist long enough to accumulate glucose
• Hereditary haemoglobin variants: Certain hemoglobinopathies can interfere with the assay and yield a falsely low A1c

4) When HbA1c is HIGH

This indicates poor glycaemic control over the past few months

Typical patterns:

• Undiagnosed or poorly controlled diabetes: Indicates that blood sugars have been running very high on average. Patients may experience symptoms like thirst, frequent urination, and weight loss
• Inadequate diabetes management: In someone with known diabetes, a rising A1c indicates that current treatment isn’t sufficient (could be due to progression of disease, poor medication adherence, or lifestyle factors).
• Prediabetes: State of above-normal glucose which heightens the risk of developing diabetes
• Iron deficiency anaemia: Can sometimes cause a mildly higher A1c (RBCs live slightly longer and accumulate more glucose)

5) Included in follow-up panel: Yes

1) What it measures

Insulin is produced by the pancreas (pancreatic beta cells) and is critical for helping cells take up glucose from the bloodstream.

2) Why it matters

Measuring insulin can help distinguish between type 1 and type 2 diabetes, investigate causes of hypoglycaemia, and assess insulin resistance. High insulin levels (hyperinsulinemia) often indicate insulin resistance (as seen in type 2 diabetes or metabolic syndrome). Very low insulin levels can indicate insulin deficiency (as in type 1 diabetes or advanced type 2)

3) When insulin is LOW

Low insulin levels mean the pancreas is not producing much insulin

Typical patterns:

• Type 1 diabetes: The immune system destroys insulin-producing cells, resulting in little to no insulin. Patients require external insulin and typically have high blood glucose
• Late-stage type 2 diabetes: Pancreatic cells may fail, and insulin production drops, causing insulin levels to become low even as blood sugar remains elevated
• Pancreatic damage: Pancreatitis, pancreatic surgery, or tumours that destroy the pancreas can lead to reduced insulin output and low levels

4) When insulin is HIGH

This is when the body is producing excess insulin relative to glucose levels

Typical patterns:

• Insulin resistance (Pre-diabetes/Type 2): In metabolic syndrome or early type 2 diabetes, the body’s tissues don’t respond well to insulin, so the pancreas compensates by secreting more; Fasting insulin can be elevated even if blood sugar is only mildly high
• Insulinoma: A rare insulin-secreting pancreatic tumour causes inappropriately high insulin, especially during fasting, leading to episodes of hypoglycaemia; Insulin is high even when glucose is dangerously low
• Obesity-related hyperinsulinemia: Elevated insulin levels as the pancreas works overtime to keep blood sugars normal
• Polycystic ovary syndrome (PCOS): Insulin resistance and hence higher insulin levels, contributing to weight gain and androgen excess

5) Included in follow-up panel: No

1) What it measures

Anti-thyroglobulin antibodies are autoantibodies directed against thyroglobulin, a protein in the thyroid gland that is involved in producing T3 and T4

2) Why it matters

The presence of anti-Tg antibodies indicates an autoimmune reaction against the thyroid. They are often found in autoimmune thyroid diseases

3) When anti-Tg antibodies are LOW/absent

This is normal and means there is no significant autoimmune response against thyroglobulin

Typical patterns:

• No autoimmune thyroid disease: Healthy individuals or those with thyroid issues not caused by autoimmunity will typically not have anti-thyroglobulin antibodies
• Some autoimmune cases: Autoimmune thyroiditis with only one type of antibody (like anti-TPO) and anti-Tg might be low or negative

4) When anti-Tg antibodies are HIGH

This indicates an autoimmune process targeting thyroid proteins

Typical patterns:

• Hashimoto’s thyroiditis: Elevated anti-Tg antibodies along with very high anti-TPO, contributes to thyroid gland destruction and hypothyroidism
• Graves’ disease: Anti-Tg antibodies, though they are more commonly positive for TSH receptor and TPO antibodies
• Thyroid cancer monitoring: Anti-Tg antibodies, if present, can interfere with thyroglobulin tests; Their presence is tracked because if they remain or rise, it can suggest persistent

5) Included in follow-up panel: No

1) What it measures

Anti-TPO antibodies are autoantibodies directed against thyroid peroxidase, an enzyme in the thyroid gland that plays a key role in making thyroid hormones

2) Why it matters

High levels indicate that the immune system is targeting the thyroid, which often correlates with thyroid dysfunction. Even before overt thyroid disease, positive anti-TPO suggests a risk of developing thyroid dysfunction in the future

3) When anti-TPO antibodies are LOW/absent

This means no significant antibody-mediated attack on the TPO enzyme

Typical patterns:

• No autoimmune thyroid disease: Healthy individuals and those with thyroid issues not caused by autoimmunity (e.g., nodules, non-autoimmune goitre)
• Seronegative autoimmunity: Hashimoto’s thyroiditis without detectable anti-TPO (or only anti-Tg)

4) When anti-TPO antibodies are HIGH

This indicates an ongoing autoimmune response against the thyroid

Typical patterns:

• Hashimoto’s thyroiditis: Elevated anti-TPO, often levels are very high; This leads to gradual thyroid destruction and hypothyroidism
• Graves’ disease: Also have anti-TPO antibodies; This indicates the presence of autoimmune thyroiditis component
• Postpartum thyroiditis: After pregnancy, some women develop transient autoimmune thyroiditis and may test positive for anti-TPO
• Other autoimmune diseases: (e.g. lupus, rheumatoid arthritis) can have anti-TPO positivity without significant thyroid dysfunction, signifies increased risk of future thyroid issues

5) Included in follow-up panel: No

1) What it measures

Free T4 measures the level of unbound thyroxine (tetraiodothyronine) in the blood. T4 is the main hormone produced by the thyroid gland, and the “free” portion is the fraction not bound to proteins, which is biologically active

2) Why it matters

Free T4 is a direct indicator of thyroid hormone output. It is interpreted alongside TSH to assess thyroid function. In hypothyroidism, free T4 is low and in hyperthyroidism, free T4 is high

3) When Free T4 is LOW

This indicates insufficient thyroid hormone levels in the blood

Typical patterns:

• Primary hypothyroidism: The thyroid gland is failing to produce enough T4 (due to Hashimoto’s thyroiditis, iodine deficiency, etc.); TSH is high; Symptoms include fatigue, weight gain, cold intolerance, dry skin
• Secondary hypothyroidism: The thyroid is normal, but the pituitary gland isn’t releasing enough TSH (due to pituitary tumour or damage); Free T4 is low and TSH is also low or normal
• Severe non-thyroidal illness (“euthyroid sick syndrome”): Free T4 may drop (often with low T3 more prominently), but this is a transient adaptive process, not true thyroid gland failure

4) When Free T4 is HIGH

This indicates excessive thyroid hormone levels

Typical patterns:

• Hyperthyroidism (Graves’ disease, toxic nodule): The thyroid gland is overactive, secreting too much T4; TSH is low; Symptoms include weight loss, rapid heartbeat, anxiety, and tremor
• Thyroid hormone overdose: Taking an excessive amount of levothyroxine (T4 medication) will raise free T4 levels and reduce TSH
• Thyroiditis phase (thyroid inflammation): In subacute or silent thyroiditis, damaged thyroid tissue can leak hormone, causing a temporary spike in free T4 and hyperthyroid symptoms, with low TSH

5) Included in follow-up panel: No

1) What it measures

Free T3 measures the level of unbound triiodothyronine in the blood. T3 is the active thyroid hormone (T4 is converted to T3 in tissues)

2) Why it matters

T3 is the most active thyroid hormone at the cellular level. Free T3 is useful for diagnosing hyperthyroidism and evaluating the severity of thyroid overactivity

3) When Free T3 is LOW

This indicates reduced active thyroid hormone

Typical patterns:

• Hypothyroidism: T3 is often low along with low T4 and high TSH
• Euthyroid sick syndrome: Free T3 commonly drops; T4 and TSH might be normal; This is an adaptive response and not true thyroid disease
• Conversion disorder (rare): Trouble converting T4 to T3, resulting in low T3 with relatively normal T4

4) When Free T3 is HIGH

This indicates an excess of active thyroid hormone

Typical patterns:

• Hyperthyroidism: Graves’ disease and toxic nodules lead to high T3 and T4; In some cases (“T3 toxicosis”), T3 is elevated out of proportion to T4 and may be the first to rise; TSH will be suppressed
• Early thyroid hormone therapy excess: When slightly over-replaced with thyroid hormone, T3 might be on the higher side (since T4 converts to T3)
• Thyroid nodules specialising in T3: Some toxic nodules predominantly secrete T3 leading to specifically high T3 levels

5) Included in follow-up panel: No

1) What it measures

TSH is a pituitary hormone that stimulates the thyroid gland to produce thyroid hormones (T3 and T4)

2) Why it matters

Elevated TSH generally indicates hypothyroidism (an underactive thyroid that isn’t making enough T4/T3, so the pituitary increases TSH to compensate). Low TSH usually indicates hyperthyroidism (overactive thyroid or excessive thyroid hormone levels suppress TSH production)

3) When TSH is HIGH

This means that the thyroid gland is underactive (primary hypothyroidism), so the pituitary gland increases TSH output to stimulate it

Typical patterns:

• Primary hypothyroidism: Causes include Hashimoto’s thyroiditis (autoimmune destruction of the thyroid), iodine deficiency, or after thyroid surgery; TSH is high, and T4/T3 are low or low-normal; Symptoms include fatigue, weight gain, cold intolerance
• Thyroid hormone withdrawal or non-adherence: Missed doses on thyroid hormone replacement will rise TSH
• Recovery from severe illness: Sometimes after non-thyroidal illness, a transient rise in TSH can occur as thyroid function normalises

4) When TSH is LOW

This means there is too much thyroid hormone (or exogenous thyroid hormone) in the body, suppressing pituitary TSH production

Typical patterns:

• Hyperthyroidism: In Graves’ disease (autoimmune hyperthyroid) or toxic nodular goitre, excess T3/T4 feedback and suppress TSH to very low levels; Symptoms include weight loss, palpitations, anxiety, heat intolerance
• Thyroid hormone over-replacement: Too high a dose of levothyroxine will make TSH low
• Secondary hypothyroidism (pituitary failure): Low TSH with low thyroid hormones indicates that pituitary isn’t producing TSH when the thyroid is underactive; Can occur with pituitary tumours or damage

5) Included in follow-up panel: No

1) What it measures

FSH is a pituitary hormone that stimulates the ovaries in women to develop eggs and produce oestrogen, and in men stimulates the testes to produce sperm

2) Why it matters

In women, FSH surges mid-cycle to trigger ovulation and is high after menopause due to the loss of oestrogen feedback. In men, relatively stable FSH is needed for sperm production; an elevated FSH in men can indicate testicular failure. Measuring FSH is useful in investigating infertility, menstrual irregularities, and suspected hypogonadism

3) When FSH is LOW

This indicates that the pituitary is not secreting much of it, often due to feedback from high sex hormone levels or a pituitary problem

Typical patterns:

• Pituitary/hypothalamic dysfunction: If the pituitary gland is under-functioning (as in hypopituitarism or conditions like Kallmann syndrome), FSH will be low, leading to under-stimulation of gonads (secondary hypogonadism)
• High sex hormone levels: During certain phases of the menstrual cycle (mid-luteal phase when oestrogen/progesterone are high), FSH naturally is low. In cases of oestrogen-secreting ovarian tumours, FSH can be suppressed. In men, exogenous testosterone or anabolic steroid use provides negative feedback, causing low FSH and subsequently low sperm counts

4) When FSH is HIGH

This indicates that the gonads are not producing enough hormones, so the pituitary increases FSH output

Typical patterns:

• Menopause (ovarian failure): In women, as the ovaries run out of eggs and oestrogen production drops, FSH rises very high. Postmenopausal women have persistently high FSH levels. Premature ovarian insufficiency (ovarian failure before age 40) also shows high FSH
• Primary ovarian insufficiency: Causes include autoimmune ovarian damage, genetic conditions like Turner syndrome, or after chemotherapy; FSH will be elevated due to low oestrogen/inhibin
• Primary testicular failure: In men testicular failure (primary hypogonadism) such as from Klinefelter syndrome, orchitis (e.g., mumps), or after chemotherapy; Sperm production is impaired, and the pituitary secretes more FSH to stimulate the testes
• Certain infertility scenarios: Elevated FSH in a younger woman with irregular periods suggests reduced ovarian reserve

5) Included in follow-up panel: No

1) What it measures

LH is a pituitary hormone that, in women, triggers ovulation and stimulates the ovaries to produce progesterone, and in men stimulates the Leydig cells in the testes to produce testosterone

2) Why it matters

In women, a surge in LH mid-cycle causes ovulation; chronically elevated LH (with irregular cycles) can suggest polycystic ovary syndrome (where LH:FSH ratio is often high). In men, high LH indicates testicular failure (as the pituitary tries to stimulate failing testes), whereas low LH indicates a pituitary problem or negative feedback from external androgens

3) When LH is LOW

This means the pituitary output is low

Typical patterns:

• Pituitary/hypothalamic dysfunction: If the pituitary gland or hypothalamus is not functioning properly (due to tumour, injury, Kallmann syndrome, etc.), LH can be low, leading to gonadal insufficiency (secondary hypogonadism); Low LH in a man with low testosterone points to a central cause
• Suppression by high sex steroids: In both men and women, if oestrogen or testosterone levels are high (either from tumours or external sources), they suppress LH, E.g., anabolic steroid use in a male will cause low LH. In women on high-dose oestrogen (some forms of contraception), LH is low preventing ovulation

4) When LH is HIGH

This indicates the gonads are not responding (producing sex hormones), so the pituitary is in overdrive

Typical patterns:

• Menopause: In women, the ovaries no longer respond, oestrogen is low, so LH and FSH are high. LH remains elevated post-menopause. In premature ovarian failure, high LH is similarly seen
• Polycystic Ovary Syndrome (PCOS): Elevated LH:FSH ratio; LH can be inappropriately high in the early cycle, contributing to anovulation and excess androgen production from ovaries
• Primary testicular failure: In men with testicular failure (e.g., Klinefelter syndrome, post-chemotherapy, mumps orchitis), testosterone is low, so LH rises; High LH with low testosterone indicates primary hypogonadism
• Ovulation induction scenario: In a normal menstrual cycle, LH is very high during the mid-cycle surge (this is physiological and short-lived to cause ovulation)

5) Included in follow-up panel: No

1) What it measures

Oestradiol (E2) is the primary and most potent oestrogen hormone in women of childbearing age

2) Why it matters

Oestradiol is crucial for female reproductive health, regulating the menstrual cycle and supporting pregnancy. In women, oestradiol levels help evaluate ovarian function, menstrual irregularities, and menopause status. In men and postmenopausal women, oestradiol is normally low; elevated levels in these groups could indicate hormonal imbalances or oestrogen-producing tumours

3) When oestradiol is LOW

Low oestradiol in women leads to symptoms of oestrogen deficiency

Typical patterns:

• Menopause/post-menopause: Ovaries produce very little oestradiol, so levels are low; This causes symptoms like hot flashes, vaginal dryness, and bone density loss
• Premature ovarian insufficiency: If ovaries fail or are removed at a younger age, oestradiol falls similarly to menopausal levels, with high FSH/LH
• Amenorrhea from other causes: Low oestradiol can occur in hypothalamic amenorrhea (e.g., due to stress, excessive exercise, low weight) or pituitary problems; In these cases, FSH may be low or normal
• In men: Low oestradiol can result from low testosterone (since some testosterone converts to oestradiol). It might contribute to osteoporosis or low libido

4) When oestradiol is HIGH

This can cause symptoms of oestrogen excess

Typical patterns:

• Ovulation and pregnancy: Mid-cycle oestradiol peaks before ovulation, and during pregnancy oestradiol levels become very high
• PCOS: Women with polycystic ovary syndrome may have normal or slightly elevated oestradiol (often continuous moderate levels without the normal cyclic variation), along with irregular cycles
• Oestrogen-producing tumours: Ovarian tumours (e.g. granulosa cell tumours) can secrete oestradiol, leading to abnormally high levels and symptoms such as irregular bleeding or endometrial thickening; In prepubertal girls, this can cause early puberty; In postmenopausal women, it causes uterine bleeding
• Liver disease or certain medications: Severe liver cirrhosis can lead to elevated oestradiol in men (due to reduced breakdown), contributing to feminisation (spider angiomas, gynecomastia)

5) Included in follow-up panel: No

1) What it measures

Progesterone is a hormone produced mainly by the ovaries (corpus luteum after ovulation) and by the placenta during pregnancy

2) Why it matters

Progesterone prepares the uterus for pregnancy and maintains early pregnancy. In the menstrual cycle, progesterone rises after ovulation (luteal phase). Measuring progesterone can confirm whether ovulation has occurred (a mid-luteal rise indicates ovulation). It’s also used in evaluating infertility or irregular cycles, and in pregnancy to monitor placenta function in certain cases. Low progesterone in early pregnancy can indicate a non-viable pregnancy risk, whereas high progesterone outside of pregnancy can be due to ovarian cysts or luteal phase issues

3) When progesterone is LOW

This is expected in certain phases but can be problematic if it should be high

Typical patterns:

• Anovulation (no ovulation): If a woman does not ovulate in a cycle, the corpus luteum doesn’t form and progesterone remains low throughout. This leads to irregular or absent menstruation; Low mid-cycle or mid-luteal progesterone can indicate anovulatory cycles (common in conditions like PCOS)
• Luteal phase deficiency: Ovulation occurs but the corpus luteum produces insufficient progesterone or for not long enough. This can contribute to fertility issues or early miscarriage
• First trimester pregnancy complications: Low progesterone in early pregnancy may signal an issue with the pregnancy or corpus luteum; It can be a sign of potential miscarriage or ectopic pregnancy

4) When progesterone is HIGH

High progesterone occurs naturally after ovulation and in pregnancy

Typical patterns:

• Luteal phase (normal cycle): In the second half of a normal menstrual cycle, progesterone is elevated; A high level about one week after ovulation confirms that ovulation occurred
• Pregnancy: Progesterone levels rise very high during pregnancy; This is normal in the third trimester
• Luteal cyst or ovarian tumour: Certain ovarian cysts (luteal cysts) or tumours can produce excess progesterone; This might cause prolonged high progesterone levels and irregular uterine bleeding

5) Included in follow-up panel: No

1) What it measures

Prolactin is a hormone produced by the anterior pituitary gland that stimulates breast milk production (lactation)

2) Why it matters

Prolactin levels are evaluated when investigating causes of infertility, menstrual disturbances, galactorrhoea (unexpected breast milk production), or symptoms of pituitary tumours. High prolactin (hyperprolactinemia) can disrupt the reproductive hormones, leading to irregular periods or low libido and infertility. Low prolactin levels are not usually a clinical concern except as an indicator of general pituitary failure

3) When prolactin is LOW

This is generally normal in non-pregnant, non-lactating individuals. There is usually no issue with low prolactin unless considering it in the context of panhypopituitarism

Typical patterns:

• General pituitary dysfunction: If other pituitary hormones are also low, a low (or inappropriately normal) prolactin in a postpartum woman who cannot lactate might indicate pituitary damage (e.g., Sheehan’s syndrome: postpartum pituitary necrosis)
• Dopamine or medication effects: Dopamine inhibits prolactin. Certain medications that increase dopamine or dopaminergic tone could lower prolactin, but low prolactin itself doesn’t cause symptoms

4) When prolactin is HIGH

This can cause symptoms, especially related to reproductive function

Typical patterns:

• Prolactinoma: Pituitary tumour that secretes prolactin; Symptoms in women include amenorrhea (no periods) and galactorrhoea (milk discharge); In men, it can cause low libido, impotence, and sometimes breast enlargement, often with headache or vision changes if the tumour is large
• Medications: Certain drugs (antipsychotics like risperidone, antiemetics like metoclopramide) can raise prolactin by blocking dopamine; This can lead to breast milk production and menstrual changes
• Hypothyroidism: Severe primary hypothyroidism can cause moderately elevated prolactin because high TRH levels can stimulate prolactin release
• Chest wall injury or stimulation: Shingles affecting chest nerves or frequent breast stimulation can mildly elevate prolactin
• Pregnancy and lactation: During pregnancy and breastfeeding, prolactin levels are naturally high (for milk production)

5) Included in follow-up panel: No

1) What it measures

Sex hormone binding globulin (SHBG) is a protein produced mainly by the liver that binds tightly to sex hormones, especially testosterone and oestrogen, in the bloodstream. The SHBG level influences how much free (active) testosterone and oestradiol are available to tissues

2) Why it matters

High SHBG means more hormone is bound/inactive, which can reduce free testosterone. Low SHBG means more hormone is unbound, increasing the free androgen or oestrogen effects

3) When SHBG is LOW

This leads to a higher free fraction of hormones, often seen in insulin-resistant or androgen-excess states

Typical patterns:

• Insulin resistance/Metabolic syndrome: High insulin levels suppress SHBG production by the liver; Overweight individuals or those with metabolic syndrome often have low SHBG; This results in relatively higher free androgens in women (exacerbating PCOS symptoms) and can lower total testosterone readings in men (since more is free and then metabolized)
• Polycystic Ovary Syndrome (PCOS): Women with PCOS commonly have significantly low SHBG due to both hyperinsulinemia and high ovarian androgens; Low SHBG increases free testosterone, contributing to hirsutism and acne
• Hypothyroidism: An underactive thyroid can lower SHBG; Men with hypothyroidism might have low SHBG, which can lower total testosterone (though free T may be normal)
• Androgen excess or supplementation: High levels of androgens (like in anabolic steroid use in men or certain adrenal tumours in women) suppress SHBG production; Men on testosterone therapy often see SHBG drop
• Acromegaly (excess growth hormone): Growth hormone excess is known to reduce SHBG levels

4) When SHBG is HIGH

High SHBG binds more testosterone and oestradiol, often causing a lower free fraction of these hormones

Typical patterns:

• Hyperthyroidism: Excess thyroid hormone increases SHBG production, which can lower free androgen levels (sometimes contributing to low libido or gynecomastia in hyperthyroid men)
• Pregnancy or oestrogen therapy: Oestrogen strongly raises SHBG; Pregnant women have SHBG levels several times higher than normal by the third trimester; Women on high-dose oral contraceptives or hormone replacement therapy can have elevated SHBG, which lowers free testosterone; In men, high oestrogen states (like liver cirrhosis or treatment for prostate cancer) significantly raise SHBG
• Aging in men: Older men often have rising SHBG levels with age, which contributes to a drop in free testosterone even if total testosterone doesn’t fall as sharply
• Liver disease: Mild to moderate liver disease can sometimes increase SHBG, though in severe cirrhosis SHBG might paradoxically drop due to overall reduced liver synthetic capacity
• Anorexia or malnutrition: Some cases of anorexia nervosa or cachexia show high SHBG, possibly due to altered insulin/GH levels; High SHBG in anorexic women can contribute to very low free oestrogen and amenorrhea
• Certain medications: For example, anticonvulsants like phenytoin or carbamazepine can raise SHBG levels

5) Included in follow-up panel: No

1) What it measures

Testosterone is the primary male sex hormone, in the blood. It is produced mainly by the testes in men and in smaller amounts by the ovaries and adrenal glands in women

2) Why it matters

In men, low testosterone (hypogonadism) can lead to fatigue, decreased muscle, low sex drive, and erectile dysfunction. High testosterone in men is often due to anabolic steroid use or less commonly testosterone-producing tumours. In women, elevated testosterone can cause virilization (excess hair, acne, menstrual irregularities). Measuring testosterone helps diagnose causes of infertility, sexual dysfunction, or hormonal imbalances in both sexes

3) When testosterone is LOW

In men this leads to hypogonadism symptoms

Typical patterns:

• Primary hypogonadism (testicular failure): Causes include Klinefelter syndrome, mumps orchitis, chemotherapy, or testicular trauma; Testosterone is low and FSH/LH are high; Men may experience low libido, erectile dysfunction, fatigue, loss of muscle mass, and infertility
• Secondary hypogonadism (pituitary issue): The problem lies in the pituitary or hypothalamus (tumours, prolactinoma, severe stress/illness), resulting in low LH/FSH and low testosterone; Gonadotropins are low or normal
• Age-related decline: Testosterone levels gradually decrease with age (“andropause”); Older men may have levels on the lower end of normal, sometimes with subtle symptoms
• In women: Low testosterone usually has no obvious symptoms; women naturally have much lower levels; Very low androgen states (like Addison’s disease or after adrenal removal) could cause fatigue or low libido

4) When testosterone is HIGH

This can cause different effects in men and women

Typical patterns:

• Anabolic steroid or testosterone supplementation: Can lead to side effects like acne, mood changes, increased muscle mass, and testicular shrinkage with low sperm count (due to suppressed FSH/LH)
• Testosterone-secreting tumour: Leydig cell tumours of the testes can produce excess testosterone in men; In women, ovarian tumours (like androgen-secreting tumours) or adrenal tumours can cause high testosterone leading to virilization (deepened voice, facial hair, male-pattern baldness)
• Polycystic Ovary Syndrome (PCOS): Women with PCOS often have mildly elevated testosterone or other androgens; Contributes to symptoms like hirsutism (excess hair), acne, and irregular periods
• Use of certain supplements: Some “T-boosting” supplements or DHEA can slightly elevate testosterone

5) Included in follow-up panel: No

1) What it measures

Alanine aminotransferase is an enzyme mainly in liver cells that is released into the blood when liver cells are injured or stressed

2) Why it matters

ALT is a sensitive indicator of acute liver cell damage. High ALT levels signal liver inflammation or injury (e.g. in hepatitis or fatty liver disease), allowing early detection of liver issues

3) When ALT is LOW

This is generally not concerning; In advanced cirrhosis, ALT may normalise or drop (few healthy liver cells remain to release ALT)

4) When ALT is HIGH

This usually indicates liver cell injury or inflammation

Most common patterns:

• Viral hepatitis: Very high ALT in acute liver inflammation
• Non-alcoholic fatty liver disease: Moderately elevated ALT associated with metabolic syndrome (fatty liver)
• Alcoholic liver disease: Elevated ALT (often moderate); characteristically AST: ALT > 1 in alcohol-related liver injury
• Drug-induced liver injury: Certain medications or toxins cause high ALT release (acute liver cell damage)
• Cirrhosis: ALT may be high in early-stage cirrhosis (liver scarring); in late-stage cirrhosis ALT can normalise or be low as functional liver tissue is lost

5) Included in follow-up test: Yes

1) What it measures

Albumin is the most abundant protein in blood plasma, produced by the liver. It helps maintain proper fluid balance (oncotic pressure) and transports hormones, vitamins, and other substances

2) Why it matters

Albumin reflects nutritional status and liver synthetic function. Low albumin (hypoalbuminemia) leads to loss of oncotic pressure, causing oedema (swelling). It can indicate chronic illness, malnutrition, kidney protein loss, or liver failure

3) When albumin is LOW

This usually means either decreased production or increased loss of albumin, often leading to oedema if severe

Most common patterns:

• Liver cirrhosis or chronic liver disease: Low albumin from reduced production by a diseased liver
• Nephrotic syndrome: Albumin lost through the urine due to kidney damage, causing low blood albumin
• Malnutrition or protein deficiency: Low albumin due to inadequate protein intake or absorption
• Chronic inflammation: Albumin drops as a “negative acute-phase reactant” in chronic infections, cancers, or inflammatory conditions

4) When albumin is HIGH

This is rare in normal physiology and usually reflect haemoconcentration

Most common patterns:

• Dehydration: Reduced plasma volume concentrates the blood, causing a falsely high albumin concentration

5) Included in follow-up test: Yes

1) What it measures

ALP is an enzyme found in high concentration in certain tissues, mainly the liver (especially in bile duct cells) and bone (produced by osteoblasts)

2) Why it matters

Elevated ALP can indicate cholestatic liver conditions (where bile flow is obstructed or bile duct cells are affected) or high bone turnover (such as during growth or in bone disease). Low ALP is less common but can be seen in certain conditions like malnutrition or a rare genetic disorder (hypophosphatasia)

3) When ALP is HIGH

This has two major sources: liver (particularly bile ducts) and bone

Typical patterns:

• Cholestatic liver disease: Conditions that block bile flow (cholestasis) cause ALP (and typically another enzyme GGT) to rise. Examples include gallstone obstruction of the bile duct, primary biliary cholangitis (autoimmune destruction of bile ducts), primary sclerosing cholangitis, or certain drug-induced liver injuries
• Paget’s disease of bone: A disorder of excessive bone turnover in localised areas; Symptoms may include bone pain or deformities
• Rickets/Osteomalacia: Vitamin D deficiency or other causes of poor bone mineralization; In children with rickets, ALP is often markedly elevated; in adults (osteomalacia) moderately elevated
• Primary hyperparathyroidism: Excess parathyroid hormone causes increased bone resorption and formation; ALP can be elevated when bone turnover is high
• Liver cirrhosis or liver metastases: Moderate ALP elevation can be seen in liver cirrhosis, especially biliary cirrhosis. Cancers that spread to bone or liver can raise ALP (e.g. metastatic prostate or breast cancer)
• Physiological growth: Children and adolescents normally have higher ALP levels due to bone growth
• Pregnancy: The placenta produces an ALP isoenzyme, so ALP can be mildly elevated in the third trimester (this is normal and returns to baseline after delivery)

4) When ALP is LOW

This is less common and often not symptomatic by itself, but it can be a clue in specific contexts

Typical patterns:

• Malnutrition or zinc deficiency: Severe zinc deficiency can lower ALP levels. General malnutrition or protein deficiency can also reduce liver production of ALP and bone activity
• Hypophosphatasia: A rare genetic disorder where the ALP enzyme is defective, resulting in abnormally low ALP levels; This causes poor bone mineralization and dental problems
• Hypothyroidism: Can cause mildly low ALP (because metabolism and bone turnover are reduced)
• Pernicious anaemia (B₁₂ deficiency): Severe B₁₂ deficiency can be associated with low ALP, possibly due to marrow inactivity
• After certain heart bypass surgeries: Low ALP after cardiopulmonary bypass, usually of no clinical harm

5) Included in follow-up panel: Yes

1) What it measures

Aspartate aminotransferase is an enzyme found in liver, heart, and muscle tissue. It is released into the bloodstream when any of these tissues are injured

2) Why it matters

AST reflects tissue damage but is not liver specific. High AST often accompanies ALT in liver injury, but AST can also rise with muscle injury or heart attacks. Context is needed: an isolated AST increase might indicate muscle or cardiac damage, whereas AST and ALT together point to liver injury

3) When AST is LOW

This is normal and not clinically significant (indicates no tissue damage)

4) When AST is HIGH

This indicates tissue damage in liver or muscle, requiring interpretation with other tests

Most common patterns:

• Alcoholic hepatitis: AST is elevated (higher than ALT) in alcohol-related liver inflammation
• Myocardial infarction: AST rises when heart muscle is damaged (troponin is the preferred cardiac marker)
• Rhabdomyolysis or muscle injury: AST is released from injured skeletal muscle, raising blood AST
• Acute viral hepatitis: High AST along with ALT during acute liver inflammation
• Cirrhosis: Mild to moderate AST elevation in chronic liver scarring; in advanced cirrhosis AST may exceed ALT

5) Included in follow-up test: Yes

1) What it measures

Gamma-glutamyl transferase is an enzyme related to liver and bile duct function. It indicates liver/biliary health and is especially sensitive to bile flow issues and alcohol effect on the liver

2) Why it matters

GGT is often used to confirm cholestasis or alcohol-related liver enzyme induction. Higher GGT levels signal liver stress or cholestatic damage (often paralleling ALP elevations) and can help confirm that an elevated ALP is of liver origin

3) When GGT is LOW

This is normal and is not clinically significant

4) When GGT is HIGH

This usually points to liver or bile duct strain, or enzyme induction from substances like alcohol

Most common patterns:

• Chronic alcohol abuse: Elevated GGT as a sensitive indicator of alcohol-induced liver enzyme induction
• Bile duct obstruction (cholestasis): High GGT along with ALP in blocked bile flow (cholestatic liver injury)
• Non-alcoholic fatty liver disease: Moderately elevated GGT associated with fatty liver (metabolic syndrome)
• Certain medications: Enzyme-inducing drugs (e.g., antiepileptics like phenytoin or phenobarbital) can raise GGT levels
• Acute pancreatitis or bile duct stone: Can transiently elevate GGT if bile flow is impeded during the episode

5) Included in follow-up test: Yes

1) What it measures

Bilirubin is a yellow waste product from red blood cell breakdown. It is processed by the liver and excreted in bile

2) Why it matters

Bilirubin levels show how effectively the liver is metabolizing and excreting this waste. Elevated bilirubin leads to jaundice (yellowing of skin/eyes). High bilirubin can result from increased production (e.g., haemolysis) or decreased clearance (liver dysfunction or bile duct blockage)

3) When bilirubin is LOW

This is expected in a healthy individual and is not a concern (indicates effective bilirubin clearance).

4) When bilirubin is HIGH

This indicates either overproduction or impaired elimination of bilirubin.

Most common patterns:

• Haemolytic anaemia: Excessive RBC destruction produces high unconjugated bilirubin
• Viral hepatitis (liver inflammation): Impaired bilirubin processing leads to high mixed (conjugated & unconjugated) bilirubin
• Bile duct obstruction: Elevated conjugated bilirubin (e.g., from gallstones or tumour causing cholestasis)
• Gilbert’s syndrome: Mild, benign increase in unconjugated bilirubin due to a common genetic variant
• Cirrhosis: Chronic liver disease with reduced bilirubin excretion, causing elevated bilirubin levels

5) Included in follow-up test: Yes

1) What it measures

Calcium is a mineral essential for strong bones and teeth, muscle contraction, nerve signalling, and blood clotting. Blood calcium levels are tightly regulated by parathyroid hormone (PTH) and vitamin D

2) Why it matters

Abnormal blood calcium affects neuromuscular function and overall metabolism. High calcium (hypercalcemia) can cause muscle weakness, kidney stones, and psychiatric symptoms. Low calcium (hypocalcaemia) causes muscle cramps, twitching, or tetany. Maintaining calcium in range is crucial for heart and nerve function

3) When calcium is LOW

Low calcium (hypocalcaemia) increases neuromuscular irritability and can lead to muscle spasms or tetany

Most common patterns:

• Vitamin D deficiency: Poor gut absorption of calcium leads to low calcium levels
• Hypoparathyroidism: Lack of PTH hormone causes low calcium (PTH normally raises blood calcium)
• Chronic kidney disease: In advanced CKD, low active vitamin D and high phosphorus contribute to low calcium levels

4) When calcium is HIGH

High calcium (hypercalcemia) can cause lethargy, kidney stones, constipation, and neurological symptoms

Most common patterns:

• Hyperparathyroidism: Excess PTH hormone causes elevated calcium (increased bone release and gut absorption of calcium)
• Malignancy: Certain cancers (especially with bone metastases or PTHrP secretion) cause high calcium levels via bone breakdown or hormone-like factors

5) Included in follow-up test: Yes

1) What it measures

Chloride is a major electrolyte in the blood that, along with sodium, helps maintain fluid balance and the body’s normal acid-base balance. It is the chief extracellular anion and contributes to osmotic pressure regulation

2) Why it matters

Chloride levels usually change in parallel with sodium and can indicate hydration status or acid-base disturbances. Abnormal chloride (too high or low) can help identify dehydration or metabolic acid-base disorders

3) When chloride is LOW

Low chloride (hypochloraemia) often results from loss of stomach acid or excessive fluid dilution

Most common patterns:

• Prolonged vomiting or metabolic alkalosis: Loss of stomach acid (e.g., persistent vomiting) and fluid causes low chloride levels

4) When chloride is HIGH

High chloride (hyperchloremia) indicates dehydration or an acid-base imbalance with excess chloride retention

Most common patterns:

• Dehydration or diabetes insipidus: Loss of water (through dehydration or diabetes insipidus) concentrates blood salts, leading to high chloride (often with high sodium)
• Hyperchloremic metabolic acidosis: Conditions like severe diarrhoea or renal tubular acidosis cause a relative rise in chloride as bicarbonate is lost, leading to an acidic, high-chloride state

5) Included in follow-up test: Yes

1) What it measures

Creatinine is a waste product from normal muscle metabolism, filtered out of the blood by the kidneys. Blood creatinine level is a key indicator of kidney filtration function and is used to calculate estimated glomerular filtration rate (eGFR)

2) Why it matters

If the kidneys are not filtering properly, creatinine accumulates in the blood (high creatinine signals kidney impairment). It is a standard measure for diagnosing and monitoring kidney disease or acute kidney injury

3) When creatinine is LOW

This is generally not concerning and can be due to lower muscle mass or increased filtration

Most common patterns:

• Hyperthyroidism: High metabolism (and slight muscle loss) can increase kidney filtration, resulting in a lower creatinine level

4) When creatinine is HIGH

This indicates reduced kidney function or other factors impairing creatinine clearance.

Most common patterns:

• Chronic kidney disease: Persistently high creatinine due to chronically reduced filtration ability
• Acute kidney injury: A sharp rise in creatinine from sudden loss of renal function (e.g., acute renal failure)
• Dehydration: Reduced kidney perfusion (low fluid volume) can transiently raise creatinine due to decreased clearance
• Rhabdomyolysis: Rapid muscle breakdown releases creatinine and other muscle components into blood, elevating creatinine levels

5) Included in follow-up test: Yes

1) What it measures

Cystatin C is a small protein produced by most cells, filtered out of the blood by the kidneys. Its blood level is used to assess kidney filtration efficiency (GFR) and is an alternative to creatinine that is less influenced by muscle mass

2) Why it matters

Cystatin C can detect early kidney dysfunction and changes in GFR, sometimes before creatinine rises. Because muscle mass doesn’t significantly affect cystatin C, it may be a more sensitive marker for mild kidney impairment or in populations with abnormal muscle mass

3) When cystatin C is LOW

This generally indicates very effective filtration and is usually not problematic. One cause of lowered cystatin C is increased metabolism

Most common patterns:

• Hyperthyroidism: Elevated metabolic rate can lower cystatin C levels (increased clearance), independent of actual GFR

4) When cystatin C is HIGH

This indicates reduced kidney filtration or certain metabolic conditions affecting its level

Most common patterns:

• Chronic kidney disease: Elevated cystatin C reflecting a reduced glomerular filtration rate (impaired kidney function)
• Acute kidney injury: Cystatin C rises quickly with acute loss of filtration (often earlier than creatinine)
• Hypothyroidism: Low thyroid function can raise cystatin C levels even if kidney function is normal
• Mild age-related decline: Gradual increases in cystatin C may detect early age-related GFR reductions before creatinine changes

5) Included in follow-up test: Yes

1) What it measures

Magnesium is an essential mineral involved in hundreds of enzyme reactions, nerve communication, muscle contraction, and maintaining a steady heart rhythm

2) Why it matters

Low magnesium (hypomagnesemia) increases muscle irritability (causing cramps, twitching, arrhythmias). High magnesium (hypermagnesemia) depresses neuromuscular function (leading to weak reflexes, low blood pressure, and in severe cases respiratory depression)

3) When magnesium is LOW

This can result from poor intake or excessive losses and leads to heightened neuromuscular excitability and arrhythmias

Most common patterns:

• Chronic alcoholism: Poor dietary intake and urinary/GI losses of magnesium lead to low Mg levels
• Malnutrition or malabsorption: Inadequate intake or gut absorption causes low magnesium
• Diuretic use: Some diuretics cause kidneys to waste magnesium, resulting in hypomagnesemia
• Chronic diarrhoea: Ongoing loss of magnesium in stool leads to low magnesium levels

4) When magnesium is HIGH

This is usually seen in the context of advanced renal impairment (since kidneys excrete magnesium). It can cause diminished neuromuscular responsiveness

Most common patterns:

• Kidney failure: Severe renal dysfunction leads to accumulation of magnesium (hypermagnesemia) because the kidneys cannot excrete it

5) Included in follow-up test: No

1) What it measures

Serum phosphate (phosphorus) is a mineral level in the blood that is important for bone strength (as part of bone mineral), energy production (ATP), and cellular function. Phosphate levels are carefully regulated by PTH (parathyroid hormone), vitamin D, and the kidneys. Most of the body’s phosphate is stored in bones

2) Why it matters

Abnormal phosphate levels can affect bone and metabolic health and often have an inverse relationship with calcium in various disorders. High phosphate (hyperphosphatemia) can lead to calcification issues and is often seen in kidney failure. Low phosphate (hypophosphatemia) can cause muscle weakness and bone problems

3) When phosphate is LOW

This can weaken bones and muscles over time

Most common patterns:

• Vitamin D deficiency: Leads to reduced intestinal phosphate absorption, causing low or low-normal phosphate levels in blood
• Hyperparathyroidism: Excess PTH causes the kidneys to waste phosphate, resulting in low serum phosphate

4) When phosphate is HIGH

This can result in calcium-phosphate deposits and secondary issues like calcifications

Most common patterns:

• Chronic kidney disease: Reduced renal excretion of phosphate causes high phosphate levels in the blood
• Hypoparathyroidism: Low PTH levels lead to decreased phosphate excretion, causing elevated phosphate
• Tumour lysis syndrome: Rapid cell destruction (e.g., during cancer therapy) releases large amounts of phosphate into the blood, raising levels

5) Included in follow-up test: Yes

1) What it measures

Potassium is a key electrolyte mostly inside cells, critical for nerve signalling, muscle contraction (including the heart muscle), and maintaining a regular heartbeat. Blood potassium reflects a balance regulated by kidneys and hormones

2) Why it matters

Both high potassium (hyperkalaemia) and low potassium (hypokalaemia) can cause dangerous heart rhythm disturbances (arrhythmias) and muscle dysfunction. Keeping potassium in range is vital for cardiac and neuromuscular stability

3) When potassium is LOW

Low potassium (hypokalaemia) can cause muscle weakness, cramps, and abnormal heart rhythms

Most common patterns:

• Diuretic use: Certain diuretics (water pills) cause loss of potassium in urine
• Vomiting or diarrhoea: Excessive loss of gastrointestinal fluids results in potassium depletion
• Hyperaldosteronism (Conn’s syndrome): An adrenal tumour or condition causing excess aldosterone leads to kidney retention of sodium and loss of potassium

4) When potassium is HIGH

High potassium (hyperkalaemia) can impair cardiac conduction and lead to life-threatening arrhythmias.

Most common patterns:

• Chronic kidney disease: Decreased renal excretion of potassium causes high potassium levels
• Addison’s disease (adrenal insufficiency): Lack of aldosterone from the adrenals means the kidneys don’t excrete potassium effectively, resulting in high potassium levels

5) Included in follow-up test: Yes

1) What it measures

Sodium is the major electrolyte in the extracellular fluid. It helps control fluid balance, maintain blood pressure, and supports normal nerve and muscle function. Serum sodium is a key indicator of hydration status and blood volume

2) Why it matters

Abnormal sodium levels affect water distribution in the body, especially in the brain. High sodium (hypernatremia) can cause brain cells to shrink (neurological symptoms like confusion or seizures). Low sodium (hyponatremia) can cause brain swelling (headache, confusion, seizures)

3) When sodium is LOW

Low sodium (hyponatremia) can cause nausea, confusion, seizures, and needs careful correction

Most common patterns:

• SIADH (Syndrome of inappropriate ADH): Excess ADH hormone causes water retention and dilutional low sodium
• Diuretic use: Certain diuretics (water pills) cause loss of sodium
• Heart failure or cirrhosis: These conditions lead to fluid retention and dilution of blood sodium (hyponatremia)
• Adrenal insufficiency (Addison’s disease): Lack of aldosterone and cortisol leads to sodium loss and low sodium levels

4) When sodium is HIGH

High sodium (hypernatremia) often indicates insufficient water relative to salt, leading to dehydration symptoms and potential neurological impairment.

Most common patterns:

• Dehydration: Water loss (e.g., sweating, limited intake) concentrates blood sodium, causing hypernatremia
• Diabetes insipidus: Inability to retain water (due to ADH deficiency or kidney resistance) leads to excessive water loss and high sodium levels

5) Included in follow-up test: Yes

1) What it measures

Urea (Blood Urea Nitrogen) is a waste product of protein metabolism produced in the liver and excreted by the kidneys. BUN levels in blood give insight into kidney filtration function, hydration status, and protein metabolism

2) Why it matters

High BUN suggests the kidneys are not excreting waste efficiently or that there is increased protein breakdown or intake. Low BUN can suggest severe liver dysfunction (since the liver isn’t making urea) or malnutrition/low protein intake. It helps differentiate causes of kidney issues and can reflect hydration (BUN rises when dehydrated)

3) When BUN is LOW

This may indicate inadequate production by the liver or very low protein availability

Most common patterns:

• Severe liver disease: The liver fails to synthesize urea from ammonia, resulting in low BUN levels
• Low protein intake or malnutrition: Insufficient dietary protein leads to less urea production, lowering BUN

4) When BUN is HIGH

High BUN can result from impaired renal excretion or increased protein catabolism

Most common patterns:

• Renal failure (kidney disease): Reduced kidney excretion causes accumulation of urea (elevated BUN)
• Dehydration: Low kidney perfusion causes more urea reabsorption, raising BUN
• Gastrointestinal bleeding: Blood in the gut is digested into protein, increasing ammonia production and hence raising BUN
• High-protein diet or corticosteroid use: Excess protein intake or tissue breakdown (stimulated by steroids) increases urea production, elevating BUN

5) Included in follow-up test: Yes

1) What it measures

Uric acid is a waste product of purine metabolism. It is normally filtered by the kidneys and excreted in urine. The blood uric acid level reflects the balance between production and elimination of uric acid

2) Why it matters

High uric acid (hyperuricemia) can lead to crystal formation in joints (gout) or kidneys (uric acid kidney stones). Persistent hyperuricemia is associated with gouty arthritis and renal stone risk and is often linked with metabolic syndrome

3) When uric acid is LOW

This is rare and usually not clinically significant (it may occur with certain medications or dietary factors, but no common disease state is defined by low uric acid)

4) When uric acid is HIGH

This indicates either increased production or decreased excretion of urate

Most common patterns:

• Gout: Elevated uric acid leads to crystallisation in joints, causing gouty arthritis (painful joint inflammation)
• Kidney stones: High uric acid in urine can form uric acid kidney stones
• Tumour lysis syndrome: Very high uric acid from rapid breakdown of cancer cells (e.g., during chemotherapy)
• Metabolic syndrome: Often associated with hyperuricemia (insulin resistance can reduce uric acid excretion)
• Chronic kidney disease: Reduced excretion by impaired kidneys can raise uric acid levels in blood

5) Included in follow-up test: Yes

1) What it measures

Vitamin D (measured as 25-hydroxyvitamin D in blood) is a fat-soluble vitamin that functions like a hormone. Vitamin D is obtained from sunlight exposure (skin synthesis) and diet/supplements

2) Why it matters

Vitamin D status is important for bone health and has broad effects on the body. Deficiency of vitamin D can lead to softened, weak bones (rickets in children, osteomalacia in adults) and contribute to osteoporosis. Adequate levels support immune function and may modulate the risk of certain chronic conditions (e.g., autoimmune diseases)

3) When Vitamin D is LOW

This can have significant health impacts, especially on bone integrity

Most common patterns:

• Rickets (children): Vitamin D deficiency in children leads to soft, deformed bones and growth plate abnormalities
• Osteomalacia (adults): Deficiency causes bone pain and softening in adults due to poor bone mineralization
• Osteoporosis: Chronic low vitamin D contributes to loss of bone density over time, increasing fracture risk (often coexists with low calcium)
• Autoimmune diseases: Low vitamin D levels are associated with higher risk of autoimmune conditions like multiple sclerosis or rheumatoid arthritis (correlation noted in studies)
• Secondary hyperparathyroidism (due to D deficiency): Chronically low vitamin D causes the parathyroid glands to overwork and secrete high PTH, as they attempt to maintain calcium levels

4) When Vitamin D is HIGH

Excessively high vitamin D levels are uncommon (usually from over-supplementation) and can cause hypercalcemia and toxicity (symptoms like nausea, kidney stones, confusion)

5) Included in follow-up test: No

1) What it measures

Urine bilirubin tests for the presence of bilirubin in urine. Normally, bilirubin is not present in urine. If bilirubin appears in urine, it is the conjugated (water-soluble) form, indicating that blood levels of conjugated bilirubin are elevated

2) Why it matters

Bilirubinuria (bilirubin in urine) is an early warning sign of cholestasis or significant liver dysfunction. It means the liver isn’t properly excreting conjugated bilirubin into bile, so it accumulates in blood and overflows into urine

3) When bilirubin (urine) is LOW

This is normal and desirable, indicating bilirubin is being handled properly by the liver

4) When bilirubin (urine) is HIGH

This means conjugated bilirubin is elevated in blood

Most common patterns:

• Obstructive jaundice: Bile duct obstruction (e.g., gallstones or tumour) causes conjugated bilirubin to back up into blood and spill into urine
• Hepatitis: Acute liver inflammation impairs bilirubin processing, leading to elevated conjugated bilirubin and some appearing in urine
• Cirrhosis: Chronic liver damage reduces bilirubin excretion, allowing bilirubin to leak into bloodstream and urine
• Dubin-Johnson or Rotor syndrome: Hereditary disorders of bilirubin conjugation/export cause conjugated bilirubin to accumulate
• Cholestatic drug injury: Certain drugs can induce cholestasis (bile flow blockage), resulting in high conjugated bilirubin in blood and urine

5) Included in follow-up test: No

1) What it measures

Urine glucose (glycosuria) tests for the presence of sugar in urine. Normally, the kidneys reabsorb glucose, so urine should contain no glucose. Glucose appears in urine when blood levels exceed the renal threshold, overwhelming the kidneys’ reabsorption capacity

2) Why it matters

Glucose in urine indicates abnormally high blood sugar levels or, rarely, a kidney tubule issue. Persistent glycosuria can lead to dehydration and electrolyte imbalances and is a clue to check blood sugar control

3) When glucose (urine) is LOW

A normal urinalysis has no glucose present, which is the expected finding and not a problem

4) When glucose (urine) is HIGH

Glycosuria (positive urine glucose) signals excessive blood glucose levels or reduced renal threshold

Most common patterns:

• Diabetes mellitus: High blood sugar exceeds kidney reabsorption capacity, causing sugar to spill into urine
• Gestational diabetes: Pregnancy-related high blood sugar can lead to glucose in urine during pregnancy
• Cushing’s syndrome or corticosteroid use: High cortisol levels (endogenous or from steroid medication) induce elevated blood glucose, which can cause glycosuria
• Rare renal glycosuria: A hereditary condition where kidney tubules can’t reabsorb glucose properly, causing glucose in urine despite normal blood sugar
• Pheochromocytoma or hyperthyroidism: Excess adrenal or thyroid hormones can raise blood glucose levels enough that some glucose appears in urine

5) Included in follow-up test: No

1) What it measures

Urine ketones measure the byproducts of fat breakdown in the body. Ketones appear in urine when the body is burning fat for energy instead of carbohydrates. This occurs during carbohydrate deprivation or inability to use glucose

2) Why it matters

The presence of ketones in urine (ketonuria) indicates a state of increased fat metabolism, which can occur in uncontrolled diabetes, prolonged fasting/starvation, or strict low-carb (ketogenic) diets. High levels of ketones, especially in diabetics, can signal diabetic ketoacidosis, a medical emergency

3) When ketones (urine) are LOW

This is normal when the body has sufficient carbohydrate availability and is not in a ketogenic state

4) When ketones (urine) are HIGH

Ketonuria means significant fat is being used for fuel

Most common patterns:

• Diabetic ketoacidosis: Very high urine ketones due to insulin deficiency (typically in type 1 diabetes) causing uncontrolled fat breakdown and acid buildup
• Prolonged fasting or starvation: With no food intake, the body burns fat for energy, producing ketones detectable in urine
• Low-carbohydrate ketogenic diet: Deliberate carb restriction leads to nutritional ketosis, with ketones present in urine
• Alcoholic ketoacidosis: Excessive alcohol intake coupled with poor nutrition causes the body to go into a kenotic state
• Prolonged vomiting or eating disorders: Severe malnutrition or carbohydrate deprivation due to vomiting or anorexia can result in ketosis and ketones in urine

5) Included in follow-up test: No

1) What it measures

Urine nitrite tests detect nitrites in urine, which are produced when certain bacteria convert urinary nitrates to nitrites

2) Why it matters

A positive nitrite test is an indicator of a bacterial urinary tract infection (UTI), because the human body does not naturally produce nitrites in urine. It suggests the presence of nitrate-reducing bacteria (commonly E. coli or similar organisms) in the urinary tract

3) When nitrite (urine) is LOW

This is normal in uninfected urine. (*Note* that some UTIs (caused by organisms that do not produce nitrite) can yield a false-negative nitrite test despite infection)

4) When nitrite (urine) is HIGH

A positive nitrite test indicates bacterial activity in urine

Most common patterns:

• Urinary tract infection (cystitis): Active infection in the bladder by nitrite-producing bacteria (e.g., E. coli) leads to nitrite-positive urine
• Asymptomatic bacteriuria: Bacteria in the urine without symptoms can still convert nitrates to nitrites, yielding a positive test
• Pyelonephritis: Kidney infection often shows nitrite positive if due to typical Enterobacteriaceae organisms (along with other signs like WBC casts)
• Contaminated sample: If a urine sample sits too long or isn’t collected cleanly, bacteria can multiply and produce nitrites, causing a false-positive result

5) Included in follow-up test: No

1) What it measures

Urine protein tests for the presence of protein (primarily albumin) in the urine. Normally, the kidneys filter blood and retain virtually all protein, so urine protein is minimal to none

2) Why it matters

Persistent protein in urine is a key marker of kidney disease. It can signal glomerular damage or other renal pathology. Proteinuria can lead to low blood protein levels and oedema if severe and is associated with worse outcomes in chronic kidney disease

3) When protein (urine) is LOW

A negative or trace urine protein is normal (no proteinuria). There is no clinical issue with having low/no protein in urine; it means the kidneys are functioning properly in this regard

4) When protein (urine) is HIGH

Proteinuria (high protein in urine) indicates abnormal leakage of protein through the kidneys

Most common patterns:

• Diabetic nephropathy: Long-standing diabetes damages glomeruli, causing protein (albumin) to leak into urine
• Glomerulonephritis: Inflammation of glomeruli (e.g., IgA nephropathy, lupus nephritis) leads to protein loss in urine
• Nephrotic syndrome: Heavy protein loss (as seen in conditions like minimal change disease or FSGS) with resultant oedema and low blood albumin
• Hypertensive kidney damage: Long-term high blood pressure injures glomeruli, causing proteinuria
• Orthostatic proteinuria: Benign condition in some young individuals where proteinuria occurs when standing; overall kidney function remains normal

5) Included in follow-up test: No

1) What it measures

Urine red blood cells (RBCs) indicate the presence of blood in the urine (haematuria). RBCs in urine suggest bleeding somewhere along the urinary tract, from kidneys down to urethra

2) Why it matters

Haematuria is a red flag that warrants investigation, as it can be due to benign causes like stones or infections, or serious causes like tumours in the urinary tract. It indicates a breach in the urinary tract’s integrity and requires identifying the source

3) When RBCs (urine) are LOW

A normal urinalysis has no RBCs (or an insignificant number). This is normal and indicates no bleeding in the urinary system

4) When RBCs (urine) are HIGH

Haematuria (many RBCs in urine) signals bleeding in the urinary tract

Most common patterns:

• Kidney stones: Stones can scratch the lining of the kidney/ureter, causing blood in urine
• Urinary tract infection: Inflammation of the bladder or kidneys (cystitis or pyelonephritis) can lead to RBCs leaking into urine
• Glomerulonephritis: Damage to glomeruli in the kidneys allows RBCs (and often protein) to pass into urine
• Bladder or kidney cancer: Tumours in the urinary tract can cause intermittent or continuous bleeding into the urine
• Polycystic kidney disease: Kidney cysts can bleed, leading to haematuria

5) Included in follow-up test: No

1) What it measures

Urine pH measures how acidic or alkaline the urine is. It reflects how the kidneys maintain acid-base balance

2) Why it matters

Extremes of urine pH can contribute to certain types of kidney stones and may indicate underlying metabolic disturbances. For example, very alkaline urine can promote struvite stone formation or indicate infection with urea-splitting bacteria, whereas very acidic urine can contribute to uric acid stone formation or signal ketoacidosis

3) When urine pH is LOW (acidic)

An acidic urine pH may result from increased acid production or dietary factors

Most common patterns:

• High protein diet or ketoacidosis: A diet rich in protein or states like diabetic or alcoholic ketoacidosis increase acid production, leading to consistently acidic urine

4) When urine pH is HIGH (alkaline)

An alkaline urine pH can occur due to certain infections or metabolic conditions

Most common patterns:

• Renal tubular acidosis: In this condition, urine remains inappropriately alkaline despite systemic acidosis (kidneys failing to acidify urine)
• UTI with urea-splitting bacteria: Infection by bacteria such as *Proteus* produces ammonia, causing urine to become alkaline (predisposes to struvite kidney stones)
• Vegetarian diet: Diet high in fruits and vegetables can make urine more alkaline
• Metabolic alkalosis: If the body has excess bicarbonate (alkalosis), some is excreted in urine, raising urine pH

5) Included in follow-up test: No

1) What it measures

Urobilinogen is a breakdown product of bilirubin formed in the intestines. A portion of urobilinogen is normally reabsorbed into the bloodstream and excreted in urine

2) Why it matters

Urobilinogen levels in urine reflect how much bilirubin is being processed and excreted. High urine urobilinogen can indicate excessive bilirubin production or incomplete liver clearance (e.g., haemolysis or hepatitis). An absence (very low level) of urobilinogen in urine can indicate obstructive jaundice (bile isn’t reaching the intestine to form urobilinogen)

3) When urobilinogen is LOW

Very low or absent urobilinogen in urine suggests that bilirubin is not reaching the gut to be converted

Most common patterns:

• Biliary obstruction: If bile ducts are blocked (e.g., gallstone, tumour), bilirubin can’t reach the intestine, so little to no urobilinogen is formed
• Severe cholestasis: In extreme bile flow blockage, urine urobilinogen drops to very low; often accompanied by pale stools and conjugated bilirubin appearing in urine

4) When urobilinogen is HIGH

This indicates increased bilirubin turnover or reduced hepatic clearance

Most common patterns:

• Haemolytic anaemia: Excessive breakdown of haemoglobin increases bilirubin production, leading to high urobilinogen levels in urine
• Viral hepatitis: Liver inflammation impairs the processing of bilirubin, so more bilirubin is converted to urobilinogen in the gut and ends up in urine
• Cirrhosis: Impaired liver processing can cause fluctuating or elevated urine urobilinogen levels (the liver doesn’t efficiently clear reabsorbed urobilinogen)

5) Included in follow-up test: No

1) What it measures

Urine white blood cells (WBCs) indicate the presence of leukocytes (pus cells) in urine, which is a sign of inflammation or infection in the urinary tract

2) Why it matters

A few WBCs in urine can be normal. Elevated amounts (pyuria) typically signal a urinary tract infection (UTI), as the immune system sends WBCs to fight bacteria in the urinary tract

3) When WBCs (urine) are LOW

A urine sample with no or minimal WBCs is normal, indicating no significant inflammation or infection in the urinary tract

4) When WBCs (urine) are HIGH

This means inflammation or infection is present in the urinary system

Most common patterns:

• Urinary tract infection: Significant pyuria due to infection in the bladder or kidneys (often with bacteria present)
• Pyelonephritis: Kidney infection leading to WBCs in urine (often WBC casts in urine, indicating renal involvement)
• Interstitial cystitis or sterile inflammation: WBCs in urine without bacterial growth, as seen in interstitial cystitis or other inflammatory conditions of the urinary tract
• Kidney stones: Stones can cause irritation of the urinary tract, leading to WBCs in urine even if no infection is present
• Tubulointerstitial nephritis: Sterile pyuria caused by inflammation of the kidney’s interstitium (often drug-induced or autoimmune), with white cells in urine despite no infection

5) Included in follow-up test: No

1) What it measures

Apolipoprotein E (ApoE) is a protein involved in the metabolism and clearance of fats (lipoproteins) from the bloodstream. ApoE exists in different genetic variants (commonly ε2, ε3, ε4). The ApoE *genotype* (genetic variant) can influence cholesterol levels and has implications for cardiovascular and neurological health

2) Why it matters

The ApoE genotype is associated with Alzheimer’s disease risk and affects lipid metabolism and cardiovascular risk. Understanding a patient’s ApoE variant can provide insight into certain disease risks and responses

3) When ApoE risk variants are present

Certain ApoE genetic variants confer higher disease risk or abnormal lipid profiles

Most common patterns:

• ApoE4 variant: Associated with increased risk of late-onset Alzheimer’s disease and higher LDL cholesterol (greater atherosclerosis risk)
• ApoE2/E2 genotype: Predisposes to dysbetalipoproteinemia (Type III hyperlipoproteinemia), causing elevated cholesterol and triglycerides and premature cardiovascular disease
• ApoE4 and acute injury/infection: Research has linked ApoE4 to worse outcomes after brain injury or infections

4) When ApoE genotype is normal (ε3/ε3)

The most common ApoE genotype is ε3/ε3, which is considered the “neutral” variant. It results in typical lipid metabolism and average risk profile (no special increase or decrease in risk beyond general population baseline)

5) Included in follow-up test: No

1) What it measures

CA-125 is a protein (tumour marker) found in the blood that is linked to ovarian tissue activity

2) Why it matters

While CA-125 is not specific (it can be elevated in various benign conditions as well), it is a useful marker for tracking known ovarian cancer (response to treatment or recurrence). It can also be elevated in gynaecological conditions like endometriosis or fibroids, as well as any irritation of the peritoneum (the lining of the abdomen)

3) When CA-125 is LOW

A low or normal CA-125 is expected in healthy individuals and suggests no active ovarian malignancy or significant ovarian inflammation (Low CA-125 is not problematic)

4) When CA-125 is HIGH

This indicates increased ovarian or peritoneal activity, which could be malignant or benign

Most common patterns:

• Ovarian cancer: Often significantly high CA-125 levels, particularly in epithelial ovarian cancers
• Endometriosis: Benign condition where tissue similar to uterine lining causes elevated CA-125 in some cases
• Uterine fibroids: Noncancerous uterine tumours that can moderately raise CA-125 levels
• Pelvic inflammatory disease: Infection/inflammation in the pelvis can sometimes elevate CA-125
• Peritoneal inflammation: Any condition causing peritonitis or fluid in the peritoneal cavity can raise CA-125, since it is also a marker of peritoneal irritation

5) Included in follow-up test: No

1) What it measures

Prostate Specific Antigen (PSA) is a protein produced by the prostate gland

2) Why it matters

PSA is used as a screening and monitoring tool for prostate conditions, including prostate cancer. Higher-than-normal PSA can occur in prostate cancer, but also in benign conditions like benign prostatic hyperplasia (BPH) or prostatitis

3) When PSA is LOW

This is normal in younger men or men without prostate disease. Low PSA is generally not a concern and indicates a low level of prostate activity (expected if the prostate is healthy and not enlarged)

4) When PSA is HIGH

This indicates increased prostate protein leakage into blood.

Most common patterns:

• Prostate cancer: Markedly elevated PSA (especially if steadily rising over time) is a red flag for prostate cancer
• Benign prostatic hyperplasia (BPH): Enlarged prostate in older men can moderately raise PSA levels
• Prostatitis: Inflammation or infection of the prostate can cause increased PSA during the acute phase
• Recent prostate manipulation: Procedures like prostate biopsy or a vigorous digital rectal exam can transiently raise PSA levels
• Ejaculation: Recent ejaculation can cause a slight, temporary increase in PSA

5) Included in follow-up test: No