Aspartate Aminotransferase (AST)
AST shows a narrower population spread than ALT but still rises in the upper tail with age, reflecting a mix of liver, muscle, and systemic disease burden across the population.
Unit: U/L · 12 slices · age and sex · 1 source
Filed under panels: Liver Function , Metabolic Panel · topics: Liver , Metabolic
Aspartate aminotransferase (AST) is measured on the standard chemistry panel and is found in liver, muscle, heart, and other tissues. Population distributions therefore reflect both hepatic and extrahepatic sources of AST elevation. These NHANES percentiles include the full US population rather than a screened healthy subgroup.
Population Distribution
Browse by Demographic
| Age (years) | male (U/L) | female (U/L) |
|---|---|---|
| 20-29 | 15–54.8 (20) | 12–28 (17) |
| 30-39 | 14–45 (22) | 12–36.7 (16) |
| 40-49 | 15–40.4 (21) | 12–37 (17) |
| 50-59 | 14.9–46 (22) | 13–32 (19) |
| 60-69 | 14–42 (20) | 13–35 (19) |
| 70+ | 13–36 (20) | 13–32 (19) |
Frequently Asked Questions
Why is AST less specific than ALT?
AST is present in liver but also in skeletal muscle, cardiac muscle, and other tissues. Elevated AST can therefore reflect liver injury, muscle injury, or broader systemic illness.
Why do AST distributions widen with age?
Older adults accumulate more chronic disease, medication exposure, alcohol-related injury, and muscle-related causes of AST elevation. That broadens the upper half of the distribution.
Are these values liver-only percentiles?
No. These are population AST percentiles, so they reflect all contributors to AST in the general population, not just liver-specific causes.