Surface antigen (HBsAg) HBsAg is the protein shell of hepatitis B virus (HBV), and HBsAg positivity is a sign that the body is infected with HBV, indicating the presence of current HBV infection. However, HBsAg negativity does not completely exclude HBV infection. HBsAg itself is not infectious, but has antigenic properties that stimulate the body to produce the corresponding antibody anti-HBs. Surface antibodies (anti-HBs) Anti-HBs positivity suggests that immunity to HBV may have developed through vaccination or natural infection in the past (latent or overt infection). Anti-HBs are protective antibodies and positive individuals can defend themselves against re-invasion by HBV. A negative anti-HBs indicates susceptibility to HBV and the need for hepatitis B vaccination. Core antigen (HBcAg) HBcAg is found in the nucleus of the infected person’s liver cells, and there is no free HBcAg in the blood, so HBcAg cannot be detected in the blood by conventional methods. Core antibodies (anti-HBc) Anti-HBc is not a protective antibody, and anti-HBc positivity has different meanings in different combinations. In the “major triple-positive” combination, it is one of the markers of active HBV replication. The e antigen (HBeAg) HBeAg is a marker of the degree of viral replication, and a positive test indicates active HBV replication, suggesting high infectivity. e antibody (anti-HBe) Anti-HBe positivity has different meanings in different combinations. In the “small triple-positive” group, a positive anti-HBe indicates a certain degree of suppression of HBV replication and less infectiousness.