Lab test

What is an AST blood test, and what does a high AST mean?

An AST blood test measures aspartate aminotransferase, an enzyme found mainly in the liver but also in the heart, muscles and other tissues. It is part of routine liver checks and the CMP, usually with ALT. ARUP Laboratories reports its AST range by instrument, and the ACG guideline grades elevations as multiples of the lab’s upper limit.

3 sources
Last reviewed October 7, 2026
Also called Aspartate aminotransferase, Aspartate transaminase, SGOT
No diagnosis, no treatment advice

Macro shot of empty clear plastic tube tips standing in a bright blue and green laboratory tray.

What does the AST test measure?

AST is an enzyme found mainly in the liver, but also in the heart, muscles and other tissues. When cells that contain AST are damaged, they release it into the blood. MedlinePlus

Why is the AST test ordered?

As part of a routine checkup or to monitor treatment of a liver problem. MedlinePlus
For symptoms of liver damage, or for higher risk because of family history, alcohol use disorder, obesity, diabetes or certain medicines. MedlinePlus

What are typical AST ranges?

ARUP Laboratories reports its AST interval "by report", because it varies by instrument. The ACG guideline grades elevations relative to the upper limit of normal (ULN) printed on your report. ARUP Laboratories

Reference ranges differ between laboratories and testing methods, and many also differ by age, sex, pregnancy or the phase of the menstrual cycle. The range printed on your own report is the one that applies to your result, and a clinician interprets it alongside your history.

How the ACG guideline grades AST or ALT elevations ACG Clinical Guideline
Grade	Level
Borderline	Under 2 times the ULN
Mild	2 to 5 times the ULN
Moderate	5 to 15 times the ULN
Above moderate	More than 15 times the ULN

What can affect AST results?

Pregnancy, exercise, certain medicines, age and sex can affect AST. MedlinePlus
Heart problems, pancreatitis, mononucleosis, deep burns, seizures and surgery can raise AST as well as liver disease. MedlinePlus
You may need to fast for up to 12 hours if AST is drawn with other tests. MedlinePlus

When should you talk to a clinician about a AST result?

A result outside the range does not always mean a condition that needs treatment; talk with the provider who ordered it, who usually reads AST with ALT. MedlinePlus

DiscoverMedica explains what a test measures and what named sources publish. It does not interpret individual results; the clinician who ordered your test, or one you choose, does.

Where can you get a AST test?

A clinician can order it as part of routine or follow-up care. Some services also let you order lab tests yourself; check that a service’s panel includes this marker, which laboratory runs it, and who reviews the result with you.

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AST Blood Test: questions, answered

What is a normal AST level?

Each laboratory prints its own AST range; ARUP Laboratories reports its interval by instrument. The ACG guideline grades an AST or ALT under 2 times the lab’s upper limit as borderline and 2 to 5 times as mild. Your clinician interprets it with ALT and your history. Pregnancy, exercise and some medicines can also shift it.

Can exercise raise AST?

Yes. MedlinePlus lists exercise among the things that can affect AST, since it is also found in muscle. Pregnancy, certain medicines, age and sex can affect it too. Mention recent hard exercise to the person ordering the test. AST is usually read with ALT, which is more specific to the liver.

Is high AST always a liver problem?

No. Because AST is also in the heart and muscles, MedlinePlus lists heart problems, pancreatitis, mononucleosis, burns and seizures among other causes. A higher ALT points more specifically to the liver, which is why the two are read together. Ask the clinician what fits your result.

Sources

Last reviewed October 7, 2026. Every source above was checked on or before that date. Educational information only, not medical advice; it does not replace a conversation with a licensed clinician. DiscoverMedica does not employ clinicians.