ALT and AST are enzymes that may change when cells are stressed or injured, but neither result explains the whole liver picture on its own. AST can also come from muscle, and the laboratory's printed interval matters.
This older URL now points readers to the consolidated UK liver blood-test guide, which covers ALT, AST, GGT, bilirubin and ALP together without treating one marker as a diagnosis.
Read ALT and AST in context
| ALT | Use the printed value, unit and interval | A marker of possible cell injury; not a complete liver-function test |
|---|---|---|
| AST | Use the printed value, unit and interval | Can also be affected by muscle and other tissues |
| The panel | Add bilirubin, GGT, ALP and albumin where reported | Patterns and clinical context matter more than one isolated result |
Do not diagnose a liver condition, blame alcohol or stop medicines from ALT or AST alone. Use the consolidated guide and clinician review.
Continue to the consolidated guide
The full liver guide explains how the markers relate, why units and intervals differ between laboratories, and which questions to take to the clinician. It is the canonical page for the liver cluster.
When to contact your healthcare team
- Follow any critical or urgent instruction printed on the report.
- Seek appropriate urgent care for severe or worsening symptoms, including yellowing of the eyes or skin with marked illness, confusion, collapse or severe abdominal pain.
- Bring the full panel and a list of medicines and supplements to a clinician rather than interpreting ALT or AST alone.
Common questions
Does a high ALT prove liver disease?
No. ALT is interpreted with the rest of the panel, the report's interval, previous results, medicines, symptoms and other context. It is not a diagnosis on its own.
Related guides
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Lafia organises the values, units and reference intervals shown on your report. Educational only; not medical advice, diagnosis, or treatment. AI-generated interpretations are not reviewed by a physician or human clinician and do not replace a clinician, laboratory, or original report. Do not use this content for emergencies; consult a qualified healthcare professional. Do not post personal laboratory results publicly.
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Medical disclaimer: Educational only; not medical advice, diagnosis, or treatment. AI-generated interpretations are not reviewed by a physician or human clinician. Do not use this content for emergencies; consult a qualified healthcare professional. Do not post personal laboratory results publicly. Reference intervals vary between laboratories—use the value, unit, date and range printed on your own report, and consult a qualified healthcare professional about your results and symptoms.