AST (aspartate aminotransferase)
AST is an enzyme of the liver, heart and muscles. It is read together with ALT.
At a glance
- Sample
- Blood
- Units
- U/L (most labs), µkat/L (Nordic labs)
- Often looked at with
- Bilirubin, ALT
- Preparation
- No special preparation is usually needed, but this test is often done together with other blood tests, and then you are asked to come fasting.
Units: U/L and µkat/L
Most labs print AST in U/L, the same number as IU/L; labs in the Nordic countries and a few others print it in µkat/L. To convert, divide U/L by 60.
µkat/L = U/L ÷ 60 · 1 µkat/L = 60 U/L
This converter changes units only. It doesn’t tell you whether a number is in or out of any range: that depends on the range printed by your own lab, and on your doctor. Soma does not diagnose and is not medical advice.
Why lab ranges differ
Each lab sets its reference range for its own method and analyser, and many ranges differ by age and sex. Two labs can print different ranges for the same blood, so a result is read against the range on its own report, not against a number from another lab or a website.
Soma charts every AST result against the range printed by the lab that measured it.
What can affect the result
- Hard exercise 1–3 days before the test: raises it.
- Hemolysis: red blood cells breaking down in the tube.
- Injections into a muscle.
If something like this applies, mention it to the doctor who reads your results.
Questions
How do I convert AST from U/L to µkat/L?
Divide U/L by 60. For example, 25 U/L is 0.42 µkat/L.
Why does my lab’s AST range differ from another lab’s?
Each lab sets its range for its own method and equipment, and many ranges differ by age and sex. That’s why a result is best read against the range printed on the same report.
How do I prepare for a AST test?
No special preparation is usually needed, but this test is often done together with other blood tests, and then you are asked to come fasting. Follow your lab’s instructions.
Related tests
Got a lab report with AST?
Share it to Soma: it reads every row on your phone, with no account and no upload, and puts your AST on one chart with your earlier results, each against the range your lab printed.
Sources
- AST Test — MedlinePlus, U.S. National Library of Medicine.
- Units: the factor from the definition of the katal (IUPAC–IFCC, Pure and Applied Chemistry, 2001).
Mention of a source doesn’t mean it endorses Soma. This page explains the test; it doesn’t diagnose and is not medical advice. Talk to your doctor about what your results mean.