From the Guidelines
To determine a positive hepatitis B (HBV) vaccination status, a blood test indicating an antibody to the hepatitis B surface antigen (HBsAg) should show a level of anti-HBs greater than or equal to 10 mIU/mL, as this is considered seroprotective 1. This level of anti-HBs indicates adequate immunity from vaccination, which is the primary goal of hepatitis B vaccination. The hepatitis B surface antibody (anti-HBs or HBsAb) test specifically measures antibodies produced against the hepatitis B surface antigen (HBsAg), a protein found on the outer envelope of the hepatitis B virus. When a person receives the hepatitis B vaccine, their immune system produces these protective antibodies in response to the surface antigen contained in the vaccine. The presence of these antibodies indicates successful immunization and protection against future hepatitis B infection. Some key points to consider when interpreting anti-HBs test results include:
- A level of anti-HBs ≥10 mIU/mL indicates immunity from vaccination 1
- Anti-HBs levels can also develop after recovery from natural infection, so clinical history should be considered when interpreting results 1
- If a patient shows inadequate anti-HBs levels despite vaccination, a booster dose may be recommended, particularly for high-risk individuals 1
- Different assays have different assay cutoff values, so it's essential to refer to the package insert of the test for the determination of actual/correct levels of anti-HBs antibodies 1 It's also important to note that postvaccination serologic testing 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 1.
From the Research
Hepatitis B Vaccination Status
To determine a positive hepatitis B (HBV) vaccination status, specifically an antibody to the hepatitis B surface antigen (HBsAg), the following blood tests are relevant:
- Hepatitis B surface antibodies (anti-HBs) test, which measures the level of antibodies against the HBsAg [(2,3,4,5,6)]
- The anti-HBs test is used to assess the seroprotection status of individuals, with a titre level of ≥10 mIU/ml indicating seroprotection [(2,3,5)]
Interpretation of Test Results
The results of the anti-HBs test can be interpreted as follows:
- A positive result (anti-HBs ≥10 mIU/ml) indicates a positive HBV vaccination status and seroprotection against HBV infection [(2,3,5)]
- A negative result (anti-HBs <10 mIU/ml) may indicate a non-responder or a loss of immunity over time [(3,4,6)]
- However, the absence of anti-HBs does not necessarily mean absence of immune response, as T helper response and memory cells may still provide protection against HBV [(4,5)]
Factors Affecting Test Results
Several factors can affect the results of the anti-HBs test, including: