Organ Health

Liver Function Test

What ALT, AST, ALP, GGT and bilirubin actually measure.

A liver function test (LFT) is a blood test that checks how well your liver is working. It measures a panel of enzymes and proteins — ALT, AST, ALP, GGT, bilirubin and albumin — that can flag liver stress, damage or disease.

What it measures

ALT

An enzyme released when liver cells are damaged — often the first marker to rise.

AST

Another liver enzyme; useful read alongside ALT.

ALP

Raised in bile duct issues and some bone conditions.

GGT

Sensitive to alcohol intake and bile duct problems.

Bilirubin

A breakdown product of red blood cells; high levels can cause jaundice.

Albumin

The main protein made by the liver; low levels suggest chronic liver impairment.

Why it matters

Many liver conditions are silent in their early stages — testing can catch issues before symptoms appear.
Alcohol intake, certain medications and intense exercise can all temporarily affect LFT results.
Results should always be interpreted alongside lifestyle and clinical history.

How testing works

Order a liver function panel as a finger-prick home kit or clinic venous draw.
Avoid alcohol for 24–48 hours before testing for the most representative reading.
Results are typically returned in 2–4 working days with reference ranges.

Compare Liver Function Test prices in the UK

Side-by-side comparison of CQC-regulated providers and UKAS-accredited laboratories. Transparent pricing, typical turnaround times and sample methods.

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Frequently asked questions

What does a high ALT mean?

Raised ALT usually indicates that liver cells are under stress. Common causes include fatty liver, alcohol, certain medications, viral hepatitis or recent strenuous exercise. A clinician will normally repeat the test and look at the full panel before any conclusion.