From the Guidelines
To confirm the development of antibodies against hepatitis B after vaccination, a blood test called the hepatitis B surface antibody (anti-HBs) test is necessary, with a level of 10 mIU/mL or higher indicating adequate protection, as recommended by the Advisory Committee on Immunization Practices 1.
Importance of Testing
The anti-HBs test measures the level of protective antibodies produced in response to the vaccine, which is crucial for determining immunity against hepatitis B virus (HBV) infection. This test is typically performed 1-2 months after completing the full vaccination series, which usually consists of 3 doses over 6 months 1.
Recommendations for Testing
Testing is particularly recommended for:
- Healthcare workers
- Immunocompromised individuals
- Those with high-risk exposures to confirm immunity If antibody levels are found to be insufficient, healthcare providers may recommend booster doses 1.
Interpretation of Test Results
A level of 10 mIU/mL or higher indicates adequate protection, while levels below 10 mIU/mL may require revaccination or booster doses 1. It is essential to note that different assays may have varying cutoff values, and the package insert of the test should be consulted to determine the actual levels of anti-HBs antibodies 1.
Clinical Implications
The anti-HBs test is a critical tool for assessing immunity against HBV infection, and its results can inform clinical management decisions, such as the need for booster doses or postexposure prophylaxis 1. By prioritizing the most recent and highest-quality study, we can ensure that our recommendations are based on the best available evidence, ultimately improving patient outcomes and reducing the risk of HBV infection 1.
From the Research
Hepatitis B Blood Test to Confirm Antibodies from Vaccine
- The hepatitis B vaccine is effective in inducing immune responses and providing protection against hepatitis B virus (HBV) infection, as shown in studies such as 2 and 3.
- Blood tests can be used to confirm the presence of antibodies against HBV, with a common measure being the level of anti-HBs (antibody to hepatitis B surface antigen) in the blood, as discussed in 4.
- A level of anti-HBs ≥ 10 mIU/mL is generally considered protective, and most individuals who receive the hepatitis B vaccine achieve this level, as reported in 3 and 5.
- The duration of protection afforded by the hepatitis B vaccine is not fully understood, but studies such as 5 suggest that it can last for at least 22 years, and possibly longer, without the need for booster doses.
- Factors that can influence the level and persistence of anti-HBs include the primary response to vaccination, age, and the presence of detectable anti-HBs before boosting, as noted in 2 and 5.
- Different testing methods, such as enzyme-linked immunoassay (EIA) and radioimmunoassay (RIA), can be used to determine anti-HBs levels, with EIA being a more specific test for protective antibody levels, as compared in 4.
- Isolated anti-HBs (i.e., anti-HBs without other markers of HBV infection) can be detected in some individuals, but its immunologic specificity and protective value are questionable, especially when levels are low, as discussed in 6.