Evaluation of tests used to screen patients with liver disorders.

There is no one test of liver function. Routine laboratory tests that are useful in screening for liver disease and following its course include serum AST, ALT, alkaline phosphatase, protein electrophoresis, prothrombin time, and bilirubin levels. The transaminase levels give a day-by-day account of the amount of hepatocellular injury and death that occurs. Alkaline phosphatase levels estimate the amount of impedance of bile flow. The prothrombin time and serum albumin level are excellent gauges of hepatic protein synthetic ability, whereas the bilirubin level is probably the best test of overall liver function. Many tests are now available that permit one to diagnose specific diseases of the liver.