Alanine Aminotransferase (ALT) Test

This test measures the level of alanine aminotransferase (ALT), formerly known as serum glutamic-pyruvic aminotransferase (SGPT). This enzyme is found in high concentrations within liver cells (hepatocytes). When these cells become inflamed or damaged (such as in viral hepatitis or drug-induced hepatitis), ALT is released into the bloodstream, leading to elevated levels. It is considered the most specific liver enzyme for liver damage.