Alanine transaminase

Alanine transaminase or ALT is (mostly) a liver enzyme. The spillover of this enzyme into blood is routinely measured as a marker of liver-cell damage. This helps distinguish liver disease caused by liver-cell damage from diseases caused by problems in biliary ducts.

ALT is markedly raised in hepatitis and other acute liver damage. The enzyme aspartate transaminase (AST) has a similar role, but this enzyme tends to be found in other tissues, such as the heart, so is not as specific to the liver.