Living with a Rare Disease: From Panic Attacks to Diagnosis

Hepatitis B virus infection is diagnosed through several laboratory tests that detect different markers in the blood. The most common initial screening test is the hepatitis B surface antigen (HBsAg) test, which detects a protein on the surface of the virus. If HBsAg is present in the blood, it indicates an active hepatitis B infection, either acute or chronic. This test is widely used because it can identify infected individuals before symptoms appear and helps prevent transmission to others.

Additional blood tests provide more detailed information about the infection status. The hepatitis B surface antibody (anti-HBs) test determines if a person has developed immunity to hepatitis B, either through vaccination or recovery from a past infection. The hepatitis B core antibody (anti-HBc) test helps distinguish between acute and chronic infections and can indicate past exposure to the virus. There are two types of core antibodies: IgM anti-HBc, which appears during acute infection, and IgG anti-HBc, which remains detectable for life after exposure.

For people diagnosed with chronic hepatitis B, doctors may order tests to measure viral load and assess liver function. The hepatitis B DNA test quantifies the amount of virus in the blood and helps monitor disease progression and treatment effectiveness. Liver function tests, including alanine aminotransferase (ALT) and aspartate aminotransferase (AST), measure enzymes released when liver cells are damaged. Elevated levels suggest active liver inflammation.

The hepatitis B e-antigen (HBeAg) and its corresponding antibody (anti-HBe) are additional markers that indicate how actively the virus is replicating. Presence of HBeAg usually means the virus is multiplying rapidly and the person is highly infectious. When anti-HBe appears and HBeAg disappears, it generally indicates lower viral activity and reduced infectiousness. These tests together help healthcare providers determine the stage of infection, guide treatment decisions, and monitor patient response to antiviral therapy.