Which marker is typically positive in a patient with a history of past hepatitis B infection?

In the context of a patient with a past hepatitis B infection, the presence of Anti-HBs, which signifies the development of antibodies against the hepatitis B surface antigen (HBsAg), is a key indicator of resolved infection. When an individual has recovered from hepatitis B and cleared the virus, they typically will have a positive result for Anti-HBs, indicating immunity to future infections.

Anti-HBs develops after the resolution of an acute hepatitis B infection or following vaccination, and it suggests that the person is no longer infectious. This marker is the hallmark of successful immunity against the hepatitis B virus, either through natural recovery or immunization.

In contrast, other markers like HBsAg indicate current infection, while HBV DNA reflects the presence of viral replication and is not a marker for past infection. Anti-HBe may indicate past infection but isn't as definitive for confirming immunity as Anti-HBs is. Thus, the presence of Anti-HBs is the correct context for indicating a history of past hepatitis B infection.