Serological markers of hepatitis B include HBsAg, anti-HBs, HBeAg, anti-HBe, anti-HBc and anti-HBc-IgM. HBsAg is a marker of HBV infection. Anti-HBs is a protective antibody and its positivity indicates immunity to HBV and is seen in people recovering from hepatitis B and those who have received hepatitis B vaccine. The conversion of HBsAg to negative and anti-HBs to positive is called HBsAg serological conversion. HBeAg is a secretory antigen. Positive e antigen often indicates strong viral replication and is an indicator of infectiousness. Anti~HBe is a protein substance produced by the body in response to the e antigen. HBeAg turns negative and anti-HBe turns positive, called HBeAg serological conversion, indicating that the virus has become less infectious, the disease is in the recovery phase, or the hepatitis B virus has mutated, when the virus can still be detected in the serum. Anti-IHBc is the core antibody of hepatitis B, divided into IgM and lgG: anti-HBc-IgM positive indicates acute phase infection, also seen in the acute attack of chronic hepatitis B. Anti-HBc-IgG positive indicates both often infection, as long as the infection has been HBV, regardless of whether the virus is cleared, this antibody is mostly positive.