A series of special blood tests can often determine whether or not the liver is functioning properly. These tests may also distinguish between acute and chronic liver disorders and between hepatitis and cholestasis (bile obstruction).
The most commonly performed blood tests include:
Serum Bilirubin - Elevated levels of
bilirubin often indicate an obstruction of bile flow or a
defect in the processing of bile by the liver. Bilirubin is
produced by the liver and is excreted in the bile.
Serum Albumin - Below-normal levels of albumin, a protein made by the liver, are associated with many chronic liver disorders and cirrhosis.
Serum Alkaline Phosphatase - Elevated levels of alkaline phosphatase, an enzyme found in the bile, usually indicate an obstruction of bile flow, liver injury, or certain cancers.
Serum Aminotransferases (transaminases, SGOT, SGPT) - These enzymes are released from damaged liver cells. They include ALT (SGPT) and AST (SGOT). They (especially ALT) are elevated in hepatitis.
Prothrombin Time (PT) - This test measures the time it takes for blood to clot. Blood clotting requires vitamin K and a protein (prothrombin) made by the liver. Liver cell damage and bile flow obstruction can both interfere with proper blood clotting.
Gamma-glutamyl Transpeptidase (GGT) - This enzyme is released into the blood when the liver is damaged especially by alcohol or in bile obstruction.
Alpha-fetoprotein (AFP) - This protein is produced by the fetal liver and testes, indicating hepatitis or cancer.
Mitochondrial Antibodies (AMA) - The presence of these antibodies can indicate primary biliary cirrhosis, chronic active hepatitis, and certain other autoimmune disorders.
» HAV IgM, HEV IgM - these detect active infection by Hepatitis A or E virus
» HCV-Ab - this detects evidence of infection by HCV virus
» HCVRNA - this detects the actual presence of HCV virus
» HBsAg, HBeAg, HBV DNA - these detect infection with Hepatitis B virus (HBV)
» Anti-HBs - the evidence of good immunity to HBV infection