What does it mean when the hep b surf ab result is reactive?

A reactive Hepatitis B surface antibody (Hep B Surf Ab) result indicates that a person has developed antibodies against the Hepatitis B virus, typically due to vaccination or a past infection that has resolved. This means the individual is likely immune to Hepatitis B and is at a lower risk of infection. However, it does not indicate an active infection, as that would be assessed by other Hepatitis B markers.