current or previously resolved. the presence of surface antibody (anti-hbs) indicates an individual with immunity to hepatitis b, whether due to previously resolved infection or due to hepatitis b vaccination. for example, an individual who has never had any exposure to hbv, either by vaccine or by infection, would test negative for the entire serology panel. an individual who has been vaccinated and never had an infection will test seropositive for anti-hbs due to vaccination and negative for markers of infection. an individual with an acute hbv infection would test positive for hbsag and anti-hbc (total and igm) while negative for anti-hbs. an individual with a chronic infection would test positive for hbsag and total anti-hbc (igm and igg), but negative for igm anti-hbc and anti-hbs. an individual who has successfully resolved their hbv infection will test negative for hbsag, positive for anti-hbc, and may test negative or positive for anti-hbs, although most will test positive.. some studies have suggested that a significant minority across all population cohorts fails to seroconvert after the standard three-dose series. for these individuals, a booster is recommended. other studies have indicated that even for those who seroconvert, the immunity conferred may decrease over time, and boosters are also recommended for immunocompromised individuals after five years. however, those who are immunocompetent may forego testing or boosters after the five-year period. individuals who receive vaccination for hbv should undergo serology testing to confirm seroconversion following the initial vaccine series as well as any boosters. those who are persistent non-responders to the booster series are unlikely to benefit from additional boosters and should instead be cautioned on prevention.