Safety of the blood supply in the United States: opportunities and controversies.

The risk for viral transmission by transfusion has been reduced dramatically through improved techniques for selecting and testing blood donors. Initiatives to further improve the safety of the blood supply, including more stringent donor qualifications, additional testing for infectious disease markers, viral inactivation processes, and refinement of transfusion decisions, are possible. However, because the risk for viral transmission by allogeneic transfusion is already low, additional measures will have limited yield and poor cost-effectiveness. Furthermore, unexpected side effects of some of these "improvements" may reduce the safety of the blood supply by introducing new risks. Cost-effectiveness analyses of blood safety initiatives have highlighted such successes as the introduction of virus-specific assays for screening donated blood and have identified other interventions that have poor cost-effectiveness estimates. They have also quantitated the threshold level at which the risks of an intervention outweigh its benefits. These analyses have had little effect on decisions about blood safety, possibly because of overwhelming fear of AIDS and difficulties in applying cost-effectiveness estimates to a politically and emotionally charged issue. Future interventions for improving blood supply safety must be evaluated thoroughly and chosen carefully so that the intended goals are met. Communication with the public should be undertaken so that the public understands that some of the desired measures may result in inefficient allocation of health care resources.