The AST is a cellular enzyme, is found in highest concentration in heart muscle, the cells of the liver, the cells of the skeletal muscle and in smaller amounts in other tissues. Although an elevated level of AST in the serum is not specific of the hepatic disease, is used mainly to diagnostic and to verify the course of this disease with other enzymes like ALT and ALP.Also it is used to control the patients after  myocardial infarction, in skeletal muscle disease and other.
Clinical diagnosis should not be made on a single test result; it should integrate clinical and other laboratory data.