Aspartate aminotransferase: liver and muscle enzyme used with ALT for injury patterns.
What it is
AST (aspartate aminotransferase) is found in liver, heart, and skeletal muscle. Reported in U/L. Not every panel includes AST; ALT is more liver-specific.
AST is less liver-specific than ALT because skeletal and cardiac muscle also contain it. Many UK panels still include it for pattern recognition with ALT.
Why it matters
AST rises with liver inflammation and also with muscle injury or strenuous exercise. The AST:ALT ratio and clinical history help; alcohol-related patterns are sometimes discussed but never diagnosed from ratio alone.
This guide is educational only and cannot diagnose you. Discuss results, especially anything outside your laboratory’s reference interval, or that does not match how you feel, with a GP or other appropriately qualified clinician.
How it affects the body
Shared muscle and liver sources explain why a marathon can raise AST without primary hepatitis.
For athletes
Expect AST bumps after eccentric muscle damage; recheck after rest if exercise-related elevation is likely. Persistent rises without training explanation need medical work-up.
