hepatic and biliary disorders
Laboratory Tests of the Liver and Gallbladder
Introduction
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 alsoAmerican College of Gastroenterology [ACG] Clinical Guideline: Evaluation of Abnormal Liver Chemistriesand the European Association for Study of Liver–Asociación Latinoamericana para el Estudio del HígadoClinical Practice Guidelines.) Many tests of liver biochemistry 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). ). Tests that detect viral hepatitis, liver inflammation, or altered immunoregulation include Serology and measurement of immunoglobulins, antibodies, and autoantibodies. Identifying the etiology of abnormal liver tests requires a combination of history and laboratory testing. A systematic approach including laboratory tests, imaging studies, and liver biopsy should be used. A few laboratory tests are diagnostic or highly suggestive 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 (PBC) (previously called primary biliary cirrhosis) Ceruloplasmin (reduced) and Diagnosis level and genetic testing for Other etiologies of liver disease are diagnoses of exclusion and are made through characteristic pattern in laboratory results, together with patient history and exclusion of other causes. 