Aspartate Aminotransferase(AST) Determination Reagent is an in vitro diagnostic quantitative test kit. This test is used for diagnosis and monitoring of liver disease. AST also known as aspartate aminotransferase, is an enzyme that exists in your liver, heart, brain, pancreas, kidneys, muscles and many tissues in your body. Although it can be found throughout your body, AST is most commonly associated with liver health.