Since the advent of HIV testing of donor blood in the mid/later 1980s, ex. 1985's ELISA, the transmission of HIV during transfusion has dropped dramatically. Prior testing of donor blood only included testing for antibodies to HIV. However, because of latent infection (the "window period" in which an individual is infectious, but has not had time to develop antibodies) many cases of HIV seropositive blood were missed. The development of a nucleic acid test for the HIV-1 RNA has dramatically lowered the rate of donor blood seropositivity to about 1 in 3 million units. As transmittance of HIV does not necessarily mean HIV infection, the latter could still occur at an even lower rate.
since the advent of hiv testing of donor blood in the mid/later 1980s ex 1985's elisa the transmission of hiv during transfusion has dropped dramatically prior testing of donor blood only included testing for antibodies to hiv however because of latent infection (the "window period" in which an individual is infectious but has not had time to develop antibodies) many cases of hiv seropositive blood were missed the development of a nucleic acid test for the hiv-1 rna has dramatically lowered the rate of donor blood seropositivity to about 1 in 3 million units as transmittance of hiv does not necessarily mean hiv infection the latter could still occur at an even lower rate