Hepatitis-associated with markers in the American Red Cross volunteer blood donor population. III. Influence of donor selection practice upon HBsAg prevalence.

The American Red Cross collects blood from a number of defined subsets of the donor population and teh proportion of blood collected from each subset varies widely from center to center. A large part of the variation in prevalence of HBsAg may be related to variations in the proportion of blood collected from plants and factories, military units and schools or colleges. We have derived a regression equation, significant at the p less than 0.001 level, which links HBsAg prevalence with these collection parameters. Using this equation, we were able to predict the prevelance of HBsAg among first-time donors in 6 of the 9 geographic divisions of the United States with an accuracy exceeding 10%. The predictions for the remaining division were within 35% of the actual value. Correlation studies were supported by measurements of true donor prevalence in three blood centers.