HBsAg and infectious virions are shed over the same course of time, with HBeAg appearing in the bloodstream at the height of viral replication. Thus, the presence of HBeAg indicates the individual is highly contagious (b). Although HBsAg can be shed after infectious virions are no longer being produced, the patient is still considered contagious, but to a lesser degree (c) than when HBeAg is present. The person is considered infectious as long as HBsAg persists, so answers d (not contagious) and e (resolved) are incorrect. The incidence of false-positive results for HBeAg is low (a), with specificities ranging from 98.6% to 99% reported, depending on the product used.