infection were not chosen, and policies that resulted in minimal change to the blood donor selection process were implemented. These policies not only provided a minimum of political risk to the blood banks and regulatory agencies in 1983, they also provided a minimum of protection from HIV for recipients of blood or blood products.
With the implementation of HIV testing in 1985, the extent of the problem of the HIV infectious agent in the blood supply was quickly understood. The perception of the safety of the blood supply changed both in the public's view and among the blood bank professionals. The era of HIV shifted the field of blood banking from one dominated by serology to one in which infectious disease transmission, donor concerns, and the quest for total safety have become paramount (Bove 1990). Several changes were introduced concerning donor screening, mainly the introduction of new laboratory tests.
Since 1985, donor screening has involved "lookback." Lookback is the tracing of a blood donor found to have anti-HIV (and who had donated in the past), to all recipients of the previous donation(s), who in turn are tested for HIV. Donor deferral lists have been used in the blood banks since the 1970s regarding donors positive for hepatitis B surface antigen (HBsAg), as well as donors linked with post-transfusion hepatitis. These lists have been extended to include donors found to be HIV positive and donors positive for other disease markers. Every donation is checked for previous donation by that donor to see if any unit from the donor has been rejected in the past.
The measures taken up to 1985 are still in effect: avoiding high-risk individuals, questions regarding HIV-associated symptoms, and confidential self-exclusion. Questions regarding foreign travel have been added in order to defer donors visiting areas endemic for malaria or those visiting central Africa, which has a high HIV prevalence. Questions regarding previous treatment with growth hormone have been added to defer previously treated donors because of the fear of transmission of Creutzfeldt-Jakob disease.
Additional screening tests for donated blood have been considered and were added after 1985, both for HIV and for hepatitis.
The anti-HIV test implemented in 1985 (ELISA) became more sensitive and specific following the first available kits. In spite of the improvement, a few