This test measures the level of aspartate aminotransferase in blood. AST is widely distributed with high concentrations in the heart, liver, skeletal muscle, kidney and erythrocytes. Damage or disease to any of these tissues such as myocardial infarction, viral hepatitis, liver necrosis, cirrhosis and muscular dystrophy may result in raised levels of AST. Although elevated serum AST is not specific for liver disease, it is used primarily to diagnose and monitor the course of liver disease (in combination with other enzymes such as ALT, ALP, and bilirubin). It has also been used to monitor patients with heart attacks, but it is much less specific than CPK isoenzyme and LDH isoenzyme for this purpose. It is a part of Liver Function Test. It is always advisable to go for complete profile, as level of each test in profile are considered while making decision on diagnosis as well as monitoring the treatment.