The test determines the amount of the enzyme aspartate aminotransferase (ASAT) in blood.
An enzyme is a protein that helps cells convert one substance into another. ASAT is present mainly in the liver and in cross-linked muscle tissue (heart and skeletal muscle). Normally, the amount of ASAT in the blood is low. When liver or muscle cells are damaged, ASAT is released into the blood. In healthy people (without liver problems and no muscle damage) the amount of ASAT is less than 25 U/l.
A slight elevation (generally a result 50-75 U/l) of ASAT can indicate alcohol abuse. But there are also conditions such as tumors, blockage of the bile ducts and liver cirrhosis that cause slightly elevated ASAT values. Injections into the muscles can increase ASAT levels, as can overextended muscle exercise. Use of medications or drugs can also affect the production of ASAT, so higher values are found.
Highly elevated ASAT values (as a rule a rash 250 U/l) occur in liver inflammation (hepatitides), whether or not caused by a virus. The high values can persist for months.
The ASAT value can be lowered during pregnancy.