<prompt> In a patient only Anti HBsAg is positive in serum, all other viral markers are negative. This indicates :Acute hepatitisChronic active hepatitisPersistent carrierImmunized person with hepatitis B vaccine  <response>: Answer is D Immunized person with hepatitis B vaccine: Isolated. Anti-HBs Ag is seen in immunization with JIB Ag. Commonly Encountered Serologic Patterns of Hepatitis B Infection: HBsAg Anti-HBs Anti-HBc HBeAg Anti-HBe Interpretation -- IgM Acute hepatitis B, high infectivity IgG Chronic hepatitis B, high infectivity -- IgG -- Late acute or chronic hepatitis B, low infectivityHBeAg--negative precore--mutant hepatitis B chronic or, rarely. acute -- -- 1. HBsAg of one subtype and heterotypic anti--HBs common 2. Process of seroconversion from HBsAg to anti-- HBs rare IgM -- -- 1. Acute hepatitis B 2. Anti--HBc window -- -- IgG -- -- 1. Low--level hepatitis B carrier 2. Hepatitis B in remote past -h IgG -- Recovery from hepatitis B -- -- 1. Immunization with HBsAg after vaccination 2. Hepatitis B in the remote past ? 3. False--positive 