Old and new tests: Where will it end?

Testing has improved the safety of the blood supply. We have excellent sero logic tests in place now and are implementing nucleic acid based tests to i dentify asymptomatic carriers of viruses during the infectious part of the pre-seroconversion (window) period. However, the blood supply was already q uite safe after a variety of other mechanisms had been put into place besid es testing to screen out individuals;lt risk of carrying the most important transfusion transmissible agents. An important safety factor is the use of volunteer, unpaid (unremunerated) blood donors. The best alternative to im plementing yet more tests to reduce, but not eliminate, the minute residual risks of transfusion transmission of such agents as HV, HBV and HCV is the application of microbial inactivation technology to blood and blood compon ents. Such microbially inactivated, cellular blood components should not ha ve the risk of transmitting infectious agents, but map have other, differen t risks, since nothing has yet been shown to be one hundred percent safe (i .e., risk free). The use of a test to detect carriers of spongiform encepha lopathies to prevent their theoretical transmission by transfusion may caus e harm to donors and might increase risk for recipients by decreasing the a vailable blood supply.