A number of blood tests are available that reflect the condition of the liver. The most common tests used in clinical practice include the serum aminotransferases, bilirubin, alkaline phosphatase, albumin, and prothrombin time. These tests are often referred to as "liver function tests," although this term is somewhat misleading since most do not accurately reflect how well the liver is functioning, and abnormal values can be caused by diseases unrelated to the liver. In addition, these tests may be normal in patients who have advanced liver disease.
Several specialized tests have also been developed (such as indocyanine green clearance), which, although uncommonly used in clinical practice, can measure specific aspects of hepatic function.
Despite their limitations, liver biochemical and function tests have many applications in clinical medicine:
●They provide a noninvasive method to screen for the presence of liver disease. The serum aminotransferases, for example, are part of a panel of tests used to screen all blood donors in the United States for the presence of transmissible viruses.
●They can be used to measure the efficacy of treatments for liver disease (such as immunosuppressant agents for autoimmune hepatitis). (See "Autoimmune hepatitis: Treatment".)