Serum liver tests are important but often problematic in evaluating patients with and without symptoms of hepatic disease. The common term “liver function tests” is misleading because most tests used in clinical practice measure hepatocellular damage not function. True liver function tests are those that measure synthesis of proteins made. by the liver (albumin, clotting factors) or the liver's capacity to metabolize drugs. A commonly ordered panel of automated tests includes bilirubin, aminotransferases, alkaline phosphatase, and γ-glutamyl transpeptidase. This article reviews patterns of elevated enzyme values encountered in liver diseases and their diagnostic limitations and provides an algorithm for evaluating abnormal liver test results.