Laboratory tests of the liver and gallbladder

[Dave Paprocki]

Laboratory tests are generally effective for the following:

Detecting hepatic dysfunction
Assessing the severity of liver injury
Monitoring the course of liver diseases and the response to treatment
Refining the diagnosis

(See also the American Gastroenterological Association Medical Position Statement, the Technical Review on evaluation of liver chemistry tests, and the European Association for Study of Liver–Asociaci#243;n Latinoamericana para el Estudio del H#237;gado Clinical Practice Guidelines.)
Many tests of liver biochemistry are called liver tests. These tests measure liver enzymes that are released into the bloodstream (eg, release of aminotransferases from injured liver cells or of alkaline phosphatase due to cholestasis) or assess liver function by evaluating hepatobiliary excretion (eg, bilirubin). Other tests are used to evaluate the liver’s synthetic capability (eg, prothrombin time [PT], usually reported as the international normalized ratio [INR]; albumin).
The most useful laboratory tests to screen for liver disorders are serum aminotransferases (the most commonly used liver tests), bilirubin, and alkaline phosphatase. Certain patterns of biochemical abnormalities help distinguish hepatocellular injury from impaired bile excretion (cholestasis—see table Common Patterns of Laboratory Test Abnormalities). Tests that detect viral hepatitis, liver inflammation, or altered immunoregulation include hepatitis serologic tests and measurement of immunoglobulins, antibodies, and autoantibodies.
A few laboratory tests are diagnostic by themselves; they include the following:

IgM antibody to hepatitis A virus (anti-HAV) for acute hepatitis A
Hepatitis B surface antigen (HBsAg) for acute and/or chronic hepatitis B
Antibody to hepatitis C virus (anti-HCV) and HCV-RNA for acute and/or chronic hepatitis C
Antimitochondrial antibody for primary biliary cholangitis (previously called primary biliary cirrhosis)
Serum ceruloplasmin (reduced) and urinary copper (elevated) for Wilson disease
Serum alpha-1 antitrypsin level and genetic testing for alpha1-antitrypsin deficiency
Alpha-fetoprotein for hepatocellular carcinoma