Educational information only. At Precursor, blood testing is requested and reviewed by a clinician and considered alongside your history and other markers, not as a stand-alone diagnosis. Testing is performed in NATA-accredited laboratories to ISO 15189 standards.

What is ALT?

ALT, or alanine aminotransferase, is an enzyme found mainly inside liver cells. When liver cells are stressed or damaged, ALT leaks into the bloodstream, so a raised level is one of the more specific blood signs that the liver is under strain. It is a core part of what is often called a liver function test.

Why it matters

Because ALT is concentrated in the liver, it is a relatively specific marker of liver-cell health. It is widely used to pick up common issues such as fatty liver, and to monitor the liver over time, particularly in the context of metabolic health, alcohol or certain medications.

What your results can mean

Higher than optimal

A raised ALT suggests liver cells are under stress. Common causes include fatty liver linked to metabolic health, alcohol, some medications and viral infections. It is interpreted alongside the other liver enzymes to understand the pattern.

Within the healthy range

An ALT in range is a reassuring sign that the liver cells are not obviously stressed, though it is always read together with the rest of the liver panel.

Reference ranges in Australia

ALT is reported in units per litre (U/L), with reference ranges that vary between laboratories and tend to differ slightly between men and women. Read your result against the range on your own report and alongside your other liver markers.

Test your liver with Precursor

ALT is most informative alongside the full liver panel. At Precursor it is measured as part of Full Advanced Bloods, a single clinician-reviewed blood draw covering your liver, heart, metabolic, hormonal, kidney, thyroid and nutrient markers together, giving you and your clinician a broad baseline to understand and track.