Hepatitis B Surface Antibody (Anti-HBs) Titer Testing
Order a quantitative anti-HBs test using enzyme-linked immunosorbent assay (ELISA) or equivalent immunoassay method to measure the hepatitis B surface antibody titer. 1
Specific Test Methodology
- The quantitative anti-HBs test should be performed using methods such as ELISA that can detect and quantify antibody levels in mIU/mL. 1
- The test must be capable of detecting the protective concentration threshold of ≥10 mIU/mL, which is the established standard for immunity according to the CDC and ACIP. 2, 1
- Quantitative methods are superior to qualitative tests because they provide the exact antibody concentration, allowing precise determination of protective immunity versus inadequate response. 1
Optimal Timing for Testing
- Testing should be performed 1-2 months after completion of the hepatitis B vaccination series to accurately assess immune response and allow adequate time for antibody development. 3, 1
- If hepatitis B immune globulin (HBIG) was administered, wait 3-4 months before testing anti-HBs, as passively acquired antibodies from HBIG can interfere with accurate assessment of vaccine response. 3
Interpretation of Results
- Anti-HBs ≥10 mIU/mL indicates protective immunity against HBV infection and is the universally accepted threshold. 2, 1, 4
- Anti-HBs levels of 1-9 mIU/mL are considered inadequate for protection, though these individuals respond better to revaccination compared to those with undetectable antibodies. 2
- Anti-HBs <10 mIU/mL after vaccination indicates lack of protective immunity and necessitates revaccination. 1
Distinguishing Vaccination from Natural Infection
- Order a complete serologic panel including HBsAg, anti-HBs, and total anti-HBc if you need to determine whether immunity is from vaccination versus resolved natural infection. 1
- Anti-HBs positive + anti-HBc negative = immunity from vaccination only. 3, 1, 4
- Anti-HBs positive + anti-HBc positive = immunity from resolved natural HBV infection. 3, 1
Special Testing Considerations
- Healthcare workers require mandatory post-vaccination anti-HBs testing 1-2 months after completing the vaccine series to ensure protection before potential occupational exposures. 1
- Hemodialysis patients need annual anti-HBs testing due to accelerated antibody waning in this population. 1
- Immunocompromised patients (HIV-infected, chemotherapy recipients, transplant patients) may require annual testing to monitor anti-HBs concentrations. 1
Common Pitfalls to Avoid
- Do not test anti-HBs too early after vaccination (before 1-2 months), as antibodies may not have reached peak levels yet. 3, 1
- Avoid testing within 3-4 months of HBIG administration, as this will detect passively acquired antibodies rather than vaccine-induced immunity. 3
- Do not use qualitative (positive/negative only) tests when quantitative results are needed to assess adequacy of immune response. 1
- Be aware that different assay methods may yield varying results, with some methods potentially underestimating anti-HBs titers compared to others. 5