A diagnosis of hepatitis B is confirmed through laboratory tests. Symptoms can be vague and do not always distinguish from acute (lasting several weeks) or chronic (lasting several years or lifelong) disease. Laboratory testing is a sure way to diagnose hepatitis B, for both acute and chronic disease.
Diagnosis of hepatitis B is more common during the chronic phase. The first step of tests is called serology. Serology tests are a category of laboratory tests that identify proteins produced by the virus (antigens) and antibodies produced by the body. Antibodies are part of the defense the body develops against the virus, and these appear after contact between white blood cells and the virus. For hepatitis B, there are three types of antigens and antibodies: core (c), surface (s), and “e.” Determining the presence of hepatitis B surface antigens or surface antibodies is essential in the diagnosis of the current disease state.
Acute hepatitis B infection is characterized by the presence of the hepatitis B surface antigen HBsAg and immunoglobulin M (IgM) antibody to the core antigen, HBcAg.
During the initial phase of infection, patients are also seropositive for HBeAg.
Chronic infection is characterized by the persistence (more than six months) of HBsAg (with or without concurrent HBeAg). Persistence of HBsAg is the principal marker of risk for developing chronic liver disease which leads to cirrhosis and hepatocellullar carcinoma (HCC) later in life. The presence of HBeAg indicates that the blood and body fluids of the infected individual are highly contagious.
With chronic infection, the number of the viral particles in the blood (HBV DNA testing), and the presence or absence of the e antigen or antibody will determine if treatment is required.
More Answers from Douglas Dieterich, MD