The hepatitis B virus (HBc) total antinuclear antibody (HBc Ab Total) test is a serological immunoassay that measures the total number of antibodies (both IgG and IgM) directed against the hepatitis B virus (HBc) core antigen. This antibody appears early during acute infection and remains positive for life, regardless of the outcome of the infection (recovery, progression to chronic infection, or even after vaccination in some rare cases). Therefore, it is the best indicator of past HBc exposure.