In a patient only Anti HBsAg is positive in serum, all other viral markers are negative. This indicates :

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