A positive HBsAg indicates the
or chronic HBV infection. A positive anti-HBs, in the
setting of a negative HBsAg, indicates immunity to HBV infection resulting from either vaccination or resolution of a prior infection. Occasionally, both anti-HBs and HBsAg are positive in the setting of chronic infection. In this case, although the HBs antibody is present, it is unable to neutralize the HBsAg, and the host remains chronically infected.