ALTBody

SydPath Information Sheet	Dr Graham Jones Department of Chemical Pathology

ALT

Physiology ALT (Alanine aminotransferase) is an enzyme with transaminase activity which is found in highest concentrations in the liver and the kidney. Small amounts are found in the pancreas, red blood cells and skeletal muscle. ALT catalyses the transfer of an ammonia group (NH₃) from alanine to a-ketoglutarate, producing pyruvate and glutamate. ALT is found in the hepatocyte cytosol and has a half-life in plasma of about 50 hours. Average within-person variation in serum activity is about 23%. ALT has been previously known as Serum Glutamic Pyruvic Transaminase (SGPT) and the Enzyme Commission reference is EC 2.6.1.2. Pathology Raised levels of ALT may be found in the circulation in patients with acute liver damage from any cause. ALT and AST elevations indicate damage to hepatocytes although ALT is much more specific for liver disease than AST. In cholestatic liver disease the ALT may be elevated but usually less than the elevation found in ALP and GGT. In rhabdomyolysis ALT may be elevated, but to a much lesser extent than the elevations in CK and AST. Causes of Elevated Serum ALT Any cause of hepatitis Acute or chronic viral infections (eg Hepatitis A, B, C; EBV) Toxic injury from drugs or chemicals (may be dose-dependent or idiosyncratic) Alcoholic hepatitis (AST commonly higher than ALT) Hypoxic hepatitis (marked by rapid fall in levels after restoration of blood supply) Primary or metastatic malignant neoplasms Heart failure Collagen vascular diseases: SLE Granulomatous diseases Cirrhosis (often only modest elevations) Biliary obstruction (ALP and GGT more elevated) Rhabdomyolysis (CK and AST markedly more elevated) Renal Infarct

Further information available for SydPath clients from Dr Graham Jones: 8382-9160

The Pathology Service of St Vincent's Hospital, Sydney Under the Care of the Sisters of Charity
Last updated 05/01/04