Definition
What AST measures
Aspartate aminotransferase is an enzyme found in the liver and also in muscle, heart, and red blood cells. It rises with liver-cell stress but is less liver-specific than ALT.
Illustrative sample band · Synthetic
26U/L
7.6Sample target 10–30 U/L42
Why it matters
How clinicians usually read it
The AST-to-ALT relationship carries information: different ratios point toward different liver and muscle stories, which is why the pair is drawn together.
When it reads low
A lower value can mean
A low AST is generally unremarkable and rarely a clinical question by itself.
When it reads high
A higher value can mean
A higher AST can come from the liver, a hard workout, or muscle injury. When AST is high but ALT is quiet, muscle is often the first suspect.
Questions for a clinician
Bring the number into a real conversation
01
Did I train hard in the days before this draw?
02
What does my AST-to-ALT pattern suggest in my situation?
03
Should a muscle marker or a repeat draw settle where this AST is from?
Educational boundary
Educational information only. Displayed ranges are illustrative sample bands, not a diagnosis, treatment plan, or substitute for the contracted laboratory report and a qualified clinician.
See it as a sample result
The sample dashboard shows an illustrative reading, target band, and trend for AST.