Aspartate Aminotransferase (AST)

Aspartate aminotransferase (AST), also called SGOT, is an enzyme found mainly in your liver and muscle, and a blood test measures how much has leaked into your bloodstream as a sign of tissue injury. For most adults, a normal serum AST falls in the single digits to roughly the low 40s U/L.

Ranges vary between labs, so compare to the range on your own lab report.

What AST measures

AST is an enzyme that helps your cells convert amino acids into energy. It lives inside liver cells but also in skeletal muscle, heart, kidney, and red blood cells. When any of those tissues are stressed or damaged, AST spills into your blood, which is why the test works as a general marker of tissue injury rather than a liver-only signal.

What high or low levels mean

A high AST most often points to a liver issue such as fatty liver disease, viral hepatitis, or alcohol-related injury, and it can also rise from certain medications and supplements, including statins and acetaminophen. Because AST is abundant in muscle, hard resistance training, endurance events, or a muscle injury can push it up too, often alongside a raised creatine kinase. AST is less liver-specific than ALT, so clinicians read the two together: an AST/ALT ratio above 2 leans toward alcohol-related liver disease, while a ratio below 1 is more typical of other liver conditions. Low AST is usually not a concern. If your level is persistently high, or you notice jaundice or abdominal pain, follow up with your clinician.

AST FAQ

Is a slightly high AST serious?

A mild elevation is common and often reflects recent exercise, alcohol, or a medication rather than disease. Your clinician will usually recheck it under normal conditions before ordering a broader workup.

What is the difference between AST and ALT?

Both are liver enzymes, but ALT is more specific to the liver. AST also comes from muscle and other tissues, so comparing the two helps pinpoint the source.

Can exercise raise AST?

Yes. Intense or unfamiliar workouts can temporarily raise AST from muscle turnover, so testing a few days after heavy training gives a cleaner result.

Read alongside your alanine aminotransferase, alkaline phosphatase, and total bilirubin results for a fuller picture of liver health.

Sources

• Medscape, Aspartate Aminotransferase (AST) Reference Range.

• IFCC multicenter study, common reference intervals for AST, ALT and GGT in serum.