Serologic testing for immunity is not necessary or recommended after routine vaccination of infants, children, or adults. Testing for anti-HBs after vaccination is recommended for the following groups whose subsequent clinical management depends on knowledge of their immune status:
- Infants born to HBsAg-positive women and infants born to women whose HBsAg status remains unknown (for example, infants surrendered shortly after birth); postvaccination serologic testing should consist of testing for anti-HBs and HBsAg and should not occur before age 9 months
- Healthcare professionals and public safety workers at risk for blood or body fluid exposure
- Hemodialysis patients (and other persons who might require outpatient hemodialysis), people living with HIV, and other immunocompromised people (such as hematopoietic stem-cell transplant [HSCT] recipients or people receiving chemotherapy), to determine the need for revaccination and the type of follow-up testing, and
- Sex partners of HBsAg-positive people, to determine if they have not achieved immunity and will need revaccination and to continue to use other methods of protection against HBV infection.
Testing of individuals other than infants should be performed 1–2 months after administration of the final dose of the vaccine series using a method that allows determination of a protective concentration of anti-HBs (10 mIU/mL or higher). Testing of infants should take place after administration of the final dose of the vaccine series when the infant is age 9 through 12 months. Testing should not be done earlier than 9 months to avoid inadvertent detection of HBIG administered at birth and to maximize the likelihood of detecting HBV infection, if present.