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Sensitivity of the test for antibody to hepatitis B surface antigen--United States.

Beginning in March 1986, some test kits for antibody to hepatitis B surface antigen (anti-HBs) were modified to increase sensitivity, and new anti-HBs tests were introduced with increased sensitivity for detecting anti-HBs. To assess the impact of this increased sensitivity on the interpretation of hepatitis B postvaccination testing results, the Food and Drug Administration (FDA) conducted a study of currently distributed anti-HBs test kits to determine the lower limits of their sensitivity relative to the World Health Organization (WHO) Anti-HBs Reference Preparation. In addition, CDC conducted a study among a group of vaccinated public safety workers to determine the positive predictive values of the current anti-HBs tests when used to evaluate immunity after hepatitis B vaccination. This report provides background to and summarizes the results of these two studies.