Hepatitis B Antibody Level of 36 mIU/mL: Interpretation and Clinical Significance
An anti-HBs level of 36 mIU/mL indicates protective immunity against hepatitis B virus infection, as this exceeds the protective threshold of ≥10 mIU/mL established by the CDC. 1, 2
Understanding Your Result
Your hepatitis B surface antibody (anti-HBs) level of 36 mIU/mL demonstrates adequate immune protection against HBV infection. 1 This antibody level can result from either:
- Vaccination-induced immunity: If you are negative for hepatitis B core antibody (anti-HBc), this indicates immunity from vaccination rather than past infection 3, 2
- Natural infection with recovery: If you are positive for anti-HBc, this indicates immunity from resolved natural infection 4, 2
Clinical Implications
For immunocompetent individuals with anti-HBs ≥10 mIU/mL, no further periodic testing or booster doses are needed, as vaccine-induced protection is long-lasting. 1, 3, 2 Studies demonstrate that protection can persist for at least 35 years after primary vaccination, even when antibody levels decline below 10 mIU/mL, due to immunologic memory. 5
Key Points About Your Protection Status:
- You are considered seroprotected with an anti-HBs level of 36 mIU/mL 1
- Long-term protection is maintained even if antibody levels eventually decline below 10 mIU/mL in the future, as immunologic memory persists 1, 3
- Booster vaccination is not recommended for immunocompetent persons who have achieved protective antibody levels 1, 2
Important Exceptions Requiring Ongoing Monitoring
Certain populations require different management despite protective antibody levels:
- Hemodialysis patients: Annual anti-HBs testing is recommended, with booster vaccination if levels fall below 10 mIU/mL 1, 2
- Immunocompromised patients (HIV infection, chemotherapy, stem cell transplant recipients): May require annual testing to assess antibody concentrations 1, 2
- Healthcare workers: Should have documented anti-HBs ≥10 mIU/mL after vaccination to ensure protection from occupational exposure 2
Clinical Pitfall to Avoid
If you received hepatitis B immune globulin (HBIG) within the past 4-6 months, your anti-HBs could represent passively transferred antibodies rather than true immunity. 1, 6 However, this scenario is uncommon and typically only relevant in specific post-exposure situations.