Alanine aminotransferase in clinical practice. A review.
 Alanine aminotransferase is an enzyme produced mainly in the liver.
 When serum activity is measured, it provides a marker of hepatic disease.
 This review explores the biochemistry and laboratory analysis of alanine aminotransferase in terms of its significance in human health and disease.
 Cut-off levels that define abnormality are rather arbitrary and this decreases the specificity of the test in apparently healthy patients.
 A small, but important, group of patients with alanine aminotransferase abnormality have underlying liver disease that may be treatable.
 Most can be diagnosed based on history, physical examination, and biochemical-serological profiles.
 Liver biopsy can complement the diagnostic process in selected circumstances.
 Literature pertaining to this is critically reviewed.
