What is the procedure for interpreting and responding to Hepatitis B (Hep B) titer test results?

Hepatitis B Titer Interpretation and Management

Critical Threshold for Immunity

Anti-HBs levels ≥10 mIU/mL are considered protective against hepatitis B virus infection, and immunocompetent persons with this level after completing the vaccine series have long-term protection without need for further periodic testing or booster doses. 1

When to Check Hepatitis B Titers

Testing for anti-HBs should be performed 1-2 months after the final vaccine dose using a method that detects protective concentrations (≥10 mIU/mL) in the following populations: 1

• Healthcare personnel (HCP) - upon hire or matriculation to ensure protection against occupational exposure 1
• Hemodialysis patients - to determine need for revaccination and ongoing monitoring 1
• HIV-infected persons and other immunocompromised individuals - including hematopoietic stem-cell transplant recipients or persons receiving chemotherapy 1
• Sex partners of HBsAg-positive persons - to determine need for revaccination and other protective methods 1
• Infants born to HBsAg-positive mothers - to confirm adequate protection 1

Interpretation Algorithm

If Anti-HBs ≥10 mIU/mL After Primary Series:

• The person is immune 1
• No further testing needed in immunocompetent individuals 1
• Annual testing may be warranted only if immunocompromised 1, 2
• Document protective immunity in the medical record 2

If Anti-HBs <10 mIU/mL After Primary Series:

Revaccinate with a complete second series (total of 6 doses when counting the original series), then retest anti-HBs 1-2 months after the final dose 1

If Anti-HBs <10 mIU/mL After Two Complete Series:

• Test for HBsAg to rule out chronic infection 1
• If HBsAg-positive: provide appropriate management and vaccinate all household, sexual, or needle-sharing contacts 1
• If HBsAg-negative: consider the person a non-responder who is susceptible to HBV infection 1
• Counsel about precautions to prevent HBV infection 1
• HBIG prophylaxis required for any known or likely exposure to HBsAg-positive sources 1

Special Populations Requiring Different Management

Immunocompromised Patients:

• Annual anti-HBs testing to assess antibody concentrations 1
• Revaccination when anti-HBs falls <10 mIU/mL 2

Hemodialysis Patients:

• Booster dose recommended if anti-HBs levels fall below 10 mIU/mL 2

Transplant Candidates/Recipients:

• Annual monitoring of anti-HBs levels 2
• Booster dose if antibody levels fall under 10 mIU/mL 2

Common Pitfalls to Avoid

Do not routinely test or revaccinate immunocompetent individuals whose anti-HBs has declined below 10 mIU/mL years after vaccination - cellular immune memory provides ongoing protection independent of antibody titers 3

Do not delay vaccination while waiting for serologic test results - administer the first vaccine dose immediately after collecting blood for testing in high-risk populations 1

Be aware that different assays have different cutoff values - refer to the package insert for actual/correct levels of anti-HBs antibodies 1

Testing unvaccinated or incompletely vaccinated persons for anti-HBs is potentially misleading - the ≥10 mIU/mL correlate of protection has only been validated for those who completed an approved vaccination series 1

Serologic Pattern Recognition

Negative HBsAg, Negative Anti-HBc, Positive Anti-HBs:

• Vaccine-derived immunity (not natural infection) 4
• No further action needed if immunocompetent 4

Testing Prior to Vaccination:

For certain high-risk groups (household/sexual/needle contacts of HBsAg-positive persons, HIV-positive persons, persons born in high-endemic regions), prevaccination testing should include anti-HBc, HBsAg, and anti-HBs to identify those already infected or immune 1