Abstract
Using data from various sources--we estimate that 14 to 19 per cent of American males 17-75 have personal histories that place them at high risk of transmitting the HIV infection while an additional 2 per cent of adult females may be similarly affected. Because roughly one fourth of either group may already be unsuited to give blood, we estimate that 10-14 per cent of adult males, and 1 per cent of females would be specifically deferred from giving blood because of personal histories of high-risk behavior. Local adjustments in the assumptions underlying these estimates are needed to apply them to given communities.