Biomarker Glossary

AST

AST (aspartate aminotransferase) is an enzyme found in the liver, heart, muscles and other tissues. AST is tested alongside ALT to assess liver function. A raised AST often points to liver damage, particularly when interpreted with the AST to ALT ratio.

Also known as: Aspartate Aminotransferase, SGOT, Aspartate Transaminase

AST is most informative when read alongside related markers like ALT and GGT. A single number rarely tells the whole story. If your reading sits outside the typical range, share the full report with your GP or healthcare professional before drawing conclusions.

What is AST?

AST is similar to ALT but less specific. It is found in the liver but also in heart muscle, skeletal muscle, kidney and red blood cells. This means raised AST can reflect liver damage, muscle injury, heart problems or red blood cell breakdown.

The AST to ALT ratio is more informative than either marker alone. A ratio above 2 is a classic sign of alcohol related liver disease. A ratio below 1 (ALT higher than AST) is typical of fatty liver and most viral hepatitis.

AST is part of every standard UK liver function test (LFT) alongside ALT, GGT, alkaline phosphatase, bilirubin and albumin.

Why test AST?

  • To investigate liver health, alongside ALT and other liver enzymes.
  • To assess possible alcohol related liver damage (where the AST to ALT ratio matters).
  • If you have muscle pain or take statins (which can raise AST and CK).
  • As part of a metabolic, biohacking or general health screen.
To investigate liver health, alongside ALT and other liver enzymes.

AST normal range (UK)

Result What it means
Men: 10 to 40 IU/L Normal
Women: 10 to 35 IU/L Normal
AST:ALT ratio below 1 Typical of fatty liver and most viral hepatitis
AST:ALT ratio above 2 Suggests alcohol related liver disease
Significantly raised AST Often reflects acute liver injury, muscle damage or heart attack (check CK and troponin)

Ranges vary slightly between laboratories. Always interpret AST alongside ALT and the AST:ALT ratio.

About these ranges. The ranges above are typical UK clinical lab ranges aligned to NHS and Royal College of Pathologists guidance. Your Chxhealth report will show the specific reference range used by our partner lab, Randox, for each marker. Lab ranges vary slightly between providers and assays. Always interpret your results in the context of the range printed on your own report.

What causes high AST?

  • Liver disease (fatty liver, hepatitis, cirrhosis)
  • Alcohol related liver damage
  • Heart attack or heart muscle injury
  • Skeletal muscle damage (intense exercise, injury, statins)
  • Red blood cell breakdown (haemolysis)
  • Coeliac disease
  • Some medications

What causes low AST?

  • Low AST is generally not clinically significant.
  • Vitamin B6 deficiency in rare cases.

Symptoms of high AST

  • Depends on the underlying cause.
  • Liver related: fatigue, upper right abdominal discomfort, jaundice in advanced cases.
  • Muscle related: muscle pain, weakness, dark urine after exercise.
  • Heart related: chest pain, breathlessness (medical emergency).

Symptoms of low AST

  • No specific symptoms.

How is AST tested?

AST is measured from a small blood sample. No fasting is required.

Avoid strenuous exercise for 24 to 48 hours before testing.

Best tested alongside ALT, GGT, alkaline phosphatase, bilirubin and albumin for a full liver picture.

Chxhealth samples are analysed by Randox, a UK laboratory accredited by UKAS. Results return in 3 to 5 working days.

How to support healthy AST levels

  • Address the underlying cause first: weight loss for fatty liver, alcohol reduction for alcohol related liver disease, muscle recovery for exercise induced rises.
  • Eat a Mediterranean style diet rich in oily fish, vegetables, olive oil and whole grains.
  • Limit alcohol to no more than 14 units per week (UK guidance).
  • Stay well hydrated. Coffee in moderation (2 to 3 cups per day) is protective.
  • Avoid unnecessary medications and supplements.

These are general lifestyle suggestions. Chxhealth is an information service. For personal medical advice, please speak to a healthcare professional.

Chxhealth panels that test AST

5 Chxhealth biomarker panels include AST. Each is analysed by Randox, a UK laboratory accredited by UKAS. Reports are delivered in 3 to 5 working days.

AST FAQs

What does the AST:ALT ratio mean?

It helps distinguish causes of liver damage. A ratio above 2 strongly suggests alcohol related liver disease. A ratio below 1 (ALT higher than AST) is typical of fatty liver and most viral hepatitis.

Can exercise raise AST?

Yes. AST is found in muscle, so heavy lifting, marathon training or any sudden burst of intense exercise can raise it for several days. Always avoid intense exercise for 24 to 48 hours before liver testing.

What is the difference between AST and ALT?

Both rise with liver damage, but ALT is more liver specific. AST is also found in heart and muscle. The two together (and the ratio) give a fuller picture than either alone.

Does AST tell you about heart attack?

AST rises in heart attack, but the modern markers used in UK A&E are troponin and creatine kinase MB. AST is no longer used to diagnose heart attack but can still rise alongside these markers.

Can AST go back to normal?

Yes, when the underlying cause is treated. Fatty liver, mild alcohol injury and medication effects often reverse within weeks to months.

Often tested with AST

The biomarkers below are commonly investigated alongside AST because they reveal connected aspects of the same physiological picture:

  • ALT: Reported together as the core liver enzyme pair.
  • GGT: Adds biliary and alcohol-sensitive context.
  • Ferritin: Iron overload conditions raise both AST and ferritin.

Choose the right test for your goal

If you are reading about AST because of a specific health goal, our buying guides walk you through which Chxhealth panels fit:

Sources and further reading

This page is informed by guidance from the NHS, NICE, Royal College of Pathologists and other UK authoritative bodies. For deeper detail or to verify the information, see:

About this page. Last reviewed: 13 May 2026. Next scheduled review: May 2027. This page has not yet been independently reviewed by a clinician. It is written from authoritative UK medical guidance (NHS, NICE, Royal College of Pathologists, peer-reviewed sources) but has not undergone formal clinical sign off.

Important. Chxhealth is a UK information service. We do not diagnose, treat or prescribe. The reference ranges and information on this page are general educational content and should not be used as a substitute for advice from a qualified healthcare professional. For any concerns about your health or results, please speak to your GP or another healthcare professional.