AST or TGO in dogs and cats, also known as aspartate aminotransferase or glutamic oxalacetic transaminase is the second most important enzyme, after ALT – TGP, with respect to liver function as well as liver damage.
This enzyme is mainly related to the skeletal muscle system and the liver, and its behavior is very similar to that of ALT.
If ALT and AST are elevated, liver damage is most likely present.
The veterinarian is experienced and knowledgeable enough to begin to suspect liver damage if the levels are elevated, but there can be muscle damage and mislead us, hence the importance of consulting with your veterinarian.
If he/she suspects that there is no liver damage he/she can look at different symptoms, as well as other lab values, for example, CK, or creatinine kinase.
There are drugs and situations that can elevate this enzyme, drugs such as rifampicin and other antibiotics, and situations such as excessive exercise. If the patient has been doing a lot of physical activity in the previous days, it is important to allow a few days to pass so as not to get false positives.
I talk about all of this in the video below: