Hepatitis B Surface Antibody Reactive: Immunity Confirmed
Your reactive (positive) Hepatitis B surface antibody (HBsAb) with non-reactive Hepatitis B core antibody indicates you are immune to Hepatitis B virus through successful vaccination, not from a past natural infection. 1, 2, 3
What Your Results Mean
Your serologic pattern demonstrates vaccine-derived immunity:
- HBsAg (surface antigen): Non-reactive = You do not have active Hepatitis B infection 1
- HBsAb (surface antibody): Reactive = You have protective antibodies against Hepatitis B 1, 2
- HBcAb (core antibody): Non-reactive = You have never had a natural Hepatitis B infection 1, 3
This specific combination confirms immunity acquired through vaccination rather than from recovering from a past infection. 2, 3
Clinical Significance
You are protected against Hepatitis B infection and cannot transmit the virus to others. 3
- The presence of HBsAb at levels ≥10 mIU/mL generally indicates protective immunity against HBV infection 3
- When both HBsAb and HBcAb are positive together, that would indicate immunity from past natural infection—which is NOT your case 3
- Your pattern (HBsAb positive alone without HBcAb) confirms successful response to previous HBV vaccination 3
Why "Abnormal" Appears on Your Report
The "abnormal" or "reactive" notation simply means the test detected antibodies—this is actually the desired and protective result after vaccination. 1 Laboratory reports flag any non-negative result as "abnormal" or "reactive" to draw attention to it, but in this context, it indicates immunity, not disease.
Do You Need Further Testing or Vaccination?
No routine booster doses or additional vaccination is recommended for immunocompetent individuals with documented vaccine response. 3
- Anti-HBs levels may decline over time, but immunocompetent individuals typically maintain protection even with declining antibody levels 3
- No further routine testing is typically required in immunocompetent individuals 2
- Routine booster doses are not recommended for immunocompetent individuals with documented seroconversion after vaccination 3
Special Circumstances Requiring Monitoring
If you ever require immunosuppressive therapy in the future, you remain protected against HBV reactivation due to the absence of anti-HBc (core antibody). 2, 3
The risk of HBV reactivation is minimal in individuals with vaccine-derived immunity because you lack HBcAb, meaning there is no prior natural infection that could reactivate. 1, 2 This is an important distinction from those who recovered from natural infection (who would be HBcAb positive and at risk for reactivation with immunosuppression). 1
However, specific scenarios warrant consideration:
- Before starting immunosuppressive therapy: Booster doses should be considered if anti-HBs levels are low 3
- Dialysis patients: Annual screening with anti-HBs may be recommended 1, 2
- Transplant recipients: Anti-HBs titers should be checked periodically as they may decline more rapidly 3
- Healthcare workers or high-risk exposures: Periodic testing may be warranted for those at ongoing risk 2
Common Pitfalls to Avoid
- Do not confuse "reactive" or "abnormal" HBsAb with disease—this indicates immunity, not infection 1, 2
- Do not assume you need booster vaccination unless you fall into specific high-risk categories requiring immunosuppression 3
- Do not worry about being infectious—you cannot transmit Hepatitis B to others with this serologic pattern 3