ALT transfers an amino group
Biomarker library
Liver Health
ALT
ALT (alanine aminotransferase) is an enzyme found mainly inside liver cells, where it helps turn amino acids into energy.
Measured in your health assessment, with a doctor to explain your result. Book yours
Why it matters
When liver cells are inflamed or damaged, ALT leaks into the blood, which makes it the most liver-specific of the routine liver enzymes. It is often the first sign of a fatty liver, which is very common and often causes no symptoms.
What a result can mean
Lower than the range
A low ALT is normal and nothing to worry about.
Higher than the range
The commonest cause of a raised ALT is fat building up in the liver (metabolic dysfunction-associated steatotic liver disease), linked with excess weight, insulin resistance and alcohol. Others include viral hepatitis, medicines and supplements, coeliac disease, intense exercise and, rarely, inherited conditions.
What can help
Losing 7 to 10% of body weight can substantially reduce liver fat and bring ALT back to normal. Cutting alcohol, sugary drinks and refined carbohydrates and being active all help; if ALT stays raised, doctors review medicines and check for viral and other causes.
Read it with
NoteGeneral educational illustration. Colours, sizes and movement are simplified. This is not a scan or a simulation of your body. General information, not personal medical advice: a doctor reads your own results with your history.
Know your ALT.
Measured in your health assessment and explained by the doctor who reviews your results.