Hepatitis B Core Antibody (anti-HBc)

What it isAn antibody against the hepatitis B core antigen, produced only after actual infection — not after vaccination.

DoesDistinguishes vaccine-induced immunity (anti-HBs positive, anti-HBc negative) from past infection (both positive).

GoodNegative anti-HBc in someone with positive anti-HBs confirms vaccine immunity.

BadPositive anti-HBc with negative surface antigen usually indicates resolved past infection but can occasionally reactivate during immunosuppression.