Is my AST (Aspartate Aminotransferase) normal?
Free blood test checker · Standard + longevity-optimal ranges
What is a normal AST level?
AST is a liver enzyme also found in the heart, muscles, and kidneys. Elevated AST can indicate liver damage, but also muscle injury or strenuous exercise — avoid heavy exercise for 48-72 hours before blood draws for accurate results. AST is most useful when compared with ALT via the De Ritis ratio (AST/ALT), which helps distinguish liver causes from other sources.
| Range | Values |
|---|---|
| Standard Reference | 10–35 U/L |
| Optimal | 10–30 U/L |
| High Risk | > 50 U/L |
What causes abnormal AST levels?
Elevated AST can be caused by liver conditions (hepatitis, fatty liver, cirrhosis), heavy alcohol use, muscle damage from intense exercise, heart damage (AST is also found in cardiac tissue), certain medications (statins, NSAIDs, acetaminophen), and celiac disease. Unlike ALT, AST is not specific to the liver.
When should you see a doctor?
See your doctor if AST is above 50 U/L on two consecutive tests (not after heavy exercise), if both AST and ALT are elevated, if you have symptoms like jaundice, abdominal pain, or dark urine, or if you regularly consume more than 2 alcoholic drinks per day.
AST and longevity
For fitness enthusiasts and biohackers, exercise-induced AST elevation is a common source of false alarms. Intense resistance training, marathon running, and high-intensity interval training can spike AST 2-3x above normal for 24-72 hours post-exercise. This is benign and reflects normal muscle fiber turnover, not liver damage. To avoid false positives, rest for 48-72 hours before venipuncture. The De Ritis ratio (AST/ALT) is an underutilized clinical tool: a ratio above 2:1 strongly correlates with alcoholic liver disease, while a ratio below 1:1 is characteristic of metabolic dysfunction-associated steatotic liver disease (MASLD, formerly NAFLD) and insulin resistance.
Where to get a AST test
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Related biomarkers
These biomarkers are often tested alongside AST for a more complete picture.
Related calculators
Composite scores that use AST as an input.
Frequently asked questions
What is a normal AST level?
Can exercise raise AST?
What is the AST/ALT (De Ritis) ratio?
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Sources: Reference ranges based on AHA/ACC, ADA, and AACE clinical guidelines. Biological variation data from Ricos/Westgard database. Longevity-optimal ranges reflect targets used by preventive and functional medicine practitioners.
Last reviewed: April 2026. This tool provides general health information and is not a substitute for professional medical advice, diagnosis, or treatment. Always consult your healthcare provider about your specific results.