Test Background ALT is an enzyme involved in the metabolism of the amino acid alanine. ALT works in a number of tissues, but its highest concentrations are found in the liver. Injury to the liver results in release of the enzyme into the blood.
Clinical Indications Diagnosis and monitoring of liver impairment. Higher specificity than aspartate transaminase (AST) for liver damage, however AST correlates better with degree of organ damage.