Decision analysis of the HTLV-III screening test for blood donors.

Recent research has identified the human T-lymphotropic virus type III (HTLV-III) as a probable etiologic agent of the acquired immune deficiency syndrome (AIDS). This has prompted the U.S. Public Health Service to recommend that all blood used for transfusions or in the manufacture of blood products be screened. An enzyme-linked immunosorbent assay (ELISA) has been approved for use as a screening test. From the perspective of the low-risk blood donor, however, our analysis indicates that the expected utility of no-testing may exceed that of testing. This is primarily due to the risk of a false-positive test result. It follows that informed low-risk individuals may be hesitant to donate blood. We support the discarding of blood that tests positive on ELISA but, to decrease donor risk, a positive confirmatory test, such as the Western blot, should be considered as necessary before the testing outcome is treated as positive from the donor's perspective. Additionally, individuals should be given the option to donate blood without being told the testing outcome.