From the Guidelines
The hepatitis B surface antibody quantitative test is the preferred method for assessing immunity, as it provides a numerical value of the antibody level in milli-international units per milliliter (mIU/mL), which is essential for determining the need for booster doses or revaccination. The quantitative test measures the exact amount of antibodies present in the blood, while the qualitative test simply determines whether antibodies are present (positive) or absent (negative) 1. In clinical practice, the quantitative test is more commonly used because it provides valuable information about the level of immunity, with a result greater than or equal to 10 mIU/mL generally considered protective against hepatitis B infection 1. This numerical value helps healthcare providers assess whether a patient has developed adequate immunity after vaccination or natural infection. The quantitative nature of the test is particularly important for monitoring immunity in high-risk individuals such as healthcare workers, immunocompromised patients, or those on dialysis, as it allows providers to determine if booster doses of the vaccine are needed when antibody levels fall below protective thresholds.
- Key points to consider when interpreting hepatitis B surface antibody quantitative test results include:
- A level of ≥10 mIU/mL is generally considered seroprotective 1
- Different assays have different assay cutoff values, which may affect the reported levels of anti-HBs 1
- The test 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) 1
- It is essential to note that the quantitative test provides more detailed information about the level of immunity, which is crucial for making informed decisions about patient care and management, as supported by the recommendations of the Advisory Committee on Immunization Practices 1.
From the Research
Hepatitis B Surface Antibody Quantitative
- The hepatitis B surface antibody quantitative is typically measured in terms of titer, which refers to the level of antibodies present in the blood [ 2 , 3 ].
- A higher titer indicates a stronger immune response and greater protection against hepatitis B virus (HBV) infection [ 4 , 5 ].
- However, the presence or absence of anti-HBs antibodies does not necessarily determine protective immunity, as other factors such as T helper response and memory cells also play a role [ 2 , 6 ].
Measurement and Interpretation
- The measurement of anti-HBs antibody levels is typically done using enzyme-linked immunoassay (ELISA) or other commercial assays [ 2 , 3 ].
- The results are usually reported in terms of milli-international units per milliliter (mIU/mL), with a titer of ≥10 mIU/mL considered protective [ 3 ].
- However, the interpretation of anti-HBs antibody levels can be complex, and factors such as the timing of measurement, vaccine type, and individual immune response must be taken into account [ 4 , 6 ].