AST stands for aspartate transaminase or aspartate aminotransferase, also known as AspAT/ASAT/AAT or serum glutamic oxaloacetic transaminase (GOT, SGOT) . It is a pyridoxal phosphate-dependent transaminase enzyme that catalyzes the reversible transfer of an α-amino group between aspartate and glutamate, making it an important enzyme in amino acid metabolism. AST is found in the liver, heart, skeletal muscle, kidneys, brain, red blood cells, and gall bladder.

AST is commonly measured clinically as a biomarker for liver health, along with serum ALT (alanine transaminase) level, and their ratio (AST/ALT ratio) . An AST blood test measures the amount of AST in the blood and is often part of a routine blood screening to check the health of the liver. High levels of AST in the blood may be a sign of liver damage or disease, but they can also indicate damage to other organs that produce AST, such as the heart or kidneys.

Other conditions that can cause elevated AST levels include heart attack, muscle injury, intense exercise, pregnancy, pancreatitis, seizures, surgery, and certain medications. However, a high AST level does not always mean that there is a medical condition that needs treatment, as many factors can affect the results, such as age, sex, diet, and certain medicines.