The normal value of aspartate aminotransferase is 15-40u/L. It is most abundant in the heart muscle and liver, and is released from the mitochondria when hepatocytes become necrotic, resulting in elevated serum aspartate amino acid transferase, which is clinically useful for diagnosing damage to the heart muscle, liver, and kidney diseases. Therefore, elevated aspartate aminotransferase is commonly seen in acute and chronic severe hepatitis, myocarditis, myocardial infarction, and nephritis. The test requires a fasting blood draw and other tests such as ultrasound to confirm the diagnosis.