Donors whose blood reacts falsely positive in transfusion microbiology screening assays need not be lost to transfusion.

Donations that repeatedly react in transfusion microbiology screening assays are usually discarded; with appropriate confirmatory testing on the index and on follow-up samples, the great majority of these can be shown to be falsely positive. Under carefully controlled conditions, with secure information transfer, these donations, although still reactive in the primary screening assays, can be made available for clinical use after testing and obtaining negative results with alternative assays from a list of assays evaluated as suitable for the release of blood donations. We will describe a generic algorithm that can be applied to all markers.