Hepatitis B is a viral infection that affects the liver. Testing for hepatitis B involves several blood tests to assess the presence and stage of the infection. Here are the commonly used tests for hepatitis B:
Hepatitis B Surface Antigen (HBsAg)
This test detects the presence of the hepatitis B surface antigen, which indicates an active hepatitis B infection. HBsAg is the first marker to appear in the blood and can be detected even before symptoms appear. A positive HBsAg test result typically indicates an ongoing infection.
Hepatitis B Core Antibody (anti-HBc)
The presence of hepatitis B core antibodies indicates a past or ongoing hepatitis B infection. It can be either IgM (anti-HBc IgM), which indicates acute infection, or IgG (anti-HBc IgG), which indicates a resolved or chronic infection.
Hepatitis B Surface Antibody (anti-HBs)
This test measures the presence of antibodies against the hepatitis B surface antigen. The presence of anti-HBs indicates immunity to hepatitis B either from past infection or vaccination.
Hepatitis B e Antigen (HBeAg) and Hepatitis B e Antibody (anti-HBe)
HBeAg is a marker of active viral replication in the body and is usually present during the acute phase of infection. Anti-HBe appears after the clearance of HBeAg and signifies a decrease in viral replication.
Hepatitis B Viral DNA (HBV DNA)
This test measures the amount of hepatitis B viral DNA in the blood. It helps determine the level of viral replication and assess the effectiveness of treatment in chronic hepatitis B cases.
These tests, along with a medical history evaluation and physical examination, help in diagnosing hepatitis B, determining the stage of infection (acute or chronic), and evaluating the need for treatment. It is important to consult a healthcare professional who can order the appropriate tests, interpret the results, and provide guidance on the management and treatment of hepatitis B.