Liver system

AST (Aspartate Aminotransferase)

AST

A liver and muscle enzyme — used alongside ALT in liver evaluation.

What is it

AST (Aspartate Aminotransferase) — in plain English.

AST is found in liver, heart, and muscle tissue. Elevation can reflect injury to any of these tissues, so AST is interpreted alongside ALT for liver-specific context.

Why it's measured

What AST can reveal.

AST has been used in liver evaluation, with the AST:ALT ratio providing additional clinical information in research literature.

Reference range

Where most laboratories draw the standard line.

Standard laboratory reference

< 40 U/L

Reference ranges vary by laboratory. Your individual reference range will appear on your test report and should be interpreted by your physician in the context of your overall health profile.

What results may indicate

Higher vs. lower AST — at a high level.

Elevated

Has been associated with liver injury, muscle injury, and certain cardiac conditions in research literature.

Lower

Is generally considered favorable.

These associations are general. They are not a personal diagnosis or prediction. Discuss your individual results with your physician in the context of your full health profile.

When it's measured

When AST is typically run.

Part of standard liver panels.

Related markers

Often measured alongside AST.

ALT (Alanine Aminotransferase)Liver systemAST : ALT RatioLiver systemGGT (Gamma-Glutamyl Transferase)Liver systemAlkaline Phosphatase (ALP)Liver systemTotal BilirubinLiver systemDirect BilirubinLiver system

Measured in

AST is one of 160 biomarkers in the Apex Panel.

A complete look at your heart, hormones, metabolism, inflammation, and longevity systems — drawn at Quest or LabCorp, reviewed by a U.S.-licensed physician.

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This information is for general educational purposes only and is not medical advice. Lab results alone are not intended to diagnose, treat, or cure any condition and do not replace the advice of a healthcare provider. OPTML does not offer medical advice, a diagnosis, medical treatment, or any form of medical opinion.