Anti-HBc (IgG and IgM) antibodies are the body’s first response to a hepatitis B virus (HBV) infection. These antibodies are directed against a portion of the HBV called the core. Anti-HBc IgG and IgM appear shortly after the symptoms and onset of the virus surface antigen (HBsAg). IgM arrives first and is then replaced by IgG. Anti-HBc IgG are interpreted in light of clinic factors and the results of other hepatitis B markers, particularly HBsAg and anti-HBs.
A negative anti-HBc IgG result may indicate the absence of a recent or previous HBV infection (negative HBsAg and anti-HBs). However, a developing infection cannot be ruled out. The combination of negative anti-HBc IgG and HBsAg results, but positive anti-HBs results indicates an individual that has been vaccinated against hepatitis B. In combination with positive HBsAg/negative anti-HBs, the negative anti-HBc IgG test may indicate an individual in the acute phase of the disease or a reactivation of the virus in a chronic carrier.
A positive anti-HBc IgG result may indicate that the individual has eliminated the virus and is now immune (negative HBsAg/positive anti-HBs) or is in a recovery phase (negative HBsAg and anti-HBs / negative or positive IgM, anti-HBc). When combined with a positive HBsAg, an active chronic infection may be suspected.