Also known as: Anti-HBc, IgM, Antibody to Hepatitis B Core Antigen, IgM, HBcAb, IgM.

HBcAb is not a protective antibody and is usually present in those chronically infected with Hepatitis B.  A positive or reactive HBcAb indicates a past or present infection, or could be a false positive.  Interpretation of the result depends on Hepatitis B surface antibody and Hepatitis B surface antigen.