Purpose and principles
Interpret hepatitis B markers as a coherent pattern, distinguish current, resolved and vaccine-derived states, and anticipate chronic disease, reactivation and transmission risk.
Hepatitis B serology becomes manageable when each marker answers a separate question. Surface antigen (HBsAg) asks whether viral antigen is currently present. Total core antibody (anti-HBc) asks whether natural infection has occurred at some time; vaccination contains surface antigen and therefore does not generate core antibody. Surface antibody (anti-HBs) asks whether circulating immunity is demonstrable. IgM anti-HBc supports recent infection but is not an infallible acute-versus-chronic discriminator. HBeAg and anti-HBe are replication-related markers, while quantitative HBV DNA directly measures viraemia and is essential when infectivity, phase or treatment is being judged.
Classic patterns are useful starting points. Acute infection usually has HBsAg and IgM anti-HBc, with anti-HBs absent. Chronic infection has persistent HBsAg and total anti-HBc, usually without anti-HBs. Resolved natural infection has anti-HBc and anti-HBs without HBsAg. Vaccine immunity has anti-HBs alone. During the uncommon serological window, HBsAg has disappeared before anti-HBs becomes detectable, leaving IgM anti-HBc as the key clue. An isolated total anti-HBc result is not a final diagnosis: repeat or confirm testing, HBV DNA, immune status, country of birth, exposure timing and planned immunosuppression determine its meaning.