AST (GOT)
AST (GOT) is a non-liver-specific enzyme marker found in several tissues. Muscle damage, haemolysis and rare cases of macro-AST may influence the result. Neither the individual value nor the AST/ALT ratio indicates the cause.
Auch bekannt als: Aspartat-Aminotransferase, GOT, De-Ritis-Quotient
What AST (GOT) measures
AST, also called GOT, is an intracellular enzyme. A catalog of laboratory tests describes a localization in the cytoplasm and mitochondria as well as in several human tissues, including liver, skeletal muscle, heart muscle and kidney. AST is therefore not a liver-specific marker. An increased serum value in itself does not allow a reliable association with the liver.
How to read a reference section
A specific AST reference range is part of the respective laboratory procedure. A laboratory test catalog is not a comparative or intervention study and does not allow a single numerical example to be transferred to all laboratories or people. The reference range on your own laboratory report is therefore decisive for the discussion of the findings.
What has been observed in bodybuilders
A small comparative human study examined 15 steroid-using bodybuilders, 10 bodybuilders without steroids, 49 hepatitis patients and 592 medical students. In both bodybuilder groups, creatine kinase (CK), AST and alanine aminotransferase (ALT) were elevated, while gamma-glutamyltransferase (GGT) remained normal. AST, ALT, and GGT were elevated in hepatitis patients; only there was a correlation between aminotransferases and GGT reported.
The pattern is consistent with, but does not prove, muscle involvement as a possible explanation. The study was small and observational, the steroid regimens were self-selected, and training load and measurement timing were not standardized. Normal GGT has not been validated as a diagnostic rule-out test against liver disease.
What the AST/ALT ratio can contribute
The AST/ALT ratio, also called the De Ritis ratio, is a context marker and not an independent diagnosis. A narrative clinical-biochemical review describes it as dependent on cause and timing. As a possible explanation, she cites different half-lives in the serum, around 18 hours for AST and 36 hours for ALT.
Therefore, simple threshold rules are not reliable: in acute viral hepatitis, AST can be above ALT; after several days of alcoholic hepatitis, ALT may be higher than AST. Muscle injury can also predominantly increase AST. There is no generally accepted healthy reference range for the quotient. The quotient alone therefore does not prove alcohol, muscle or liver origin.
Which laboratory artifacts and rare causes are involved
Hemolysis can analytically distort AST measurements. In an in vitro interference study, falsely high values for AST were described from a hemoglobin concentration of over 1.5 g/L in the method examined. This threshold is process dependent. The study does not show that prolonged stasis during any routine blood draw reliably triggers such an AST elevation.
Another rare differential diagnosis is macro-AST. A case report describes a 44-year-old woman with isolated AST elevation for 14 years, normal other liver values, normal ultrasound and two normal liver biopsies. Additional laboratory analysis identified macro-AST as the cause. This individual case does not prove frequency, but shows why “isolated increased” does not automatically mean “muscle or hemolysis”.
Which can be practically derived for strength training
For strength athletes, an increased AST is therefore initially a finding for further classification, not proof of a liver or muscle disease. The pattern of elevated CK, AST, and ALT with normal GGT observed in the small bodybuilder study may support muscle involvement, but does not separate the causes with certainty. Because of its time and cause dependency, the De Ritis quotient should not be confused with a fixed diagnostic equation.
The time of exposure, other laboratory values and persistence are relevant for the interpretation. However, the sources neither define a training-specific AST/ALT threshold nor a reliable training dose or time to normalization. Such numbers cannot be reliably derived from the findings.
When further clarification makes sense
A persistent isolated AST elevation should not be dismissed as a result of muscle or hemolysis. The case report on macro-AST shows a rare differential diagnosis but does not allow frequency estimation.
A joint increase in AST, ALT and GGT is also a pattern, not a sole diagnosis. Although the hepatitis comparison group of the bodybuilder study showed this pattern, the study did not validate a general separation rule. For a reliable classification, the reference range, measurement method, time interval from exposure and clinical context must be considered together; a single AST/ALT threshold does not replace this.
Sources
- Botros M et al. The de ritis ratio: the test of time. Clin Biochem Rev. 2013. PubMed
- Newcastle Hospitals Laboratories. Aspartate aminotransferase, serum. Seite aktualisiert am 07.07.2026. Open source
- Mbagaya W et al. Persistently raised aspartate aminotransferase (AST) due to macro-AST in a rheumatology clinic. Diagnosis (Berl). 2015. PubMed
- Dickerman RD et al. Anabolic steroid-induced hepatotoxicity: is it overstated?. Clin J Sport Med. 1999. PubMed
- Sonntag O. Haemolysis as an interference factor in clinical chemistry. J Clin Chem Clin Biochem. 1986. PubMed
This article was created using AI systems. Find out more