The diagnosis of hepatitis B virus (HBV) infection was revolutionized by the discovery of Australia antigen, now called hepatitis B surface antigen (HBsAg). During the ensuing two decades, serologic assays were established for HBsAg and other HBV antigens and antibodies. Advances in molecular biology techniques led to the development of hybridization and polymerase chain reaction (PCR) assays for direct determination of hepatitis B virus DNA (HBV DNA). The diagnosis of HBV infection can also be made by the detection of HBsAg or hepatitis B core antigen (HBcAg) in liver tissues by immunohistochemical staining and of HBV DNA by Southern hybridization, in-situ hybridization, or PCR.
This topic review will focus on the changes in hepatitis B antigens, antibodies, and DNA levels that occur during acute and chronic infection and how these tests can be used clinically. A diagnostic algorithm will be presented for using these tests to diagnose acute hepatitis, past infection, and chronic infection.
WHO SHOULD BE TESTED OR SCREENED
We test for hepatitis B virus infection using HBsAg, hepatitis B core antibody (anti-HBc), and hepatitis B surface antibody (anti-HBs) in certain groups of patients (table 1). The interpretation of positive serologic test results is described below. (See 'Diagnostic algorithms' below.)
We evaluate the following groups of patients for HBV, regardless of their vaccination history:
●Individuals who have signs and symptoms of acute hepatitis. (See "Clinical manifestations and natural history of hepatitis B virus infection".)