Provision of phenotype-matched blood units: no need for pre-transfusion antibody screening

Background and Objectives. The Hong Kong government is planning to introduc e an electronic smart identity card for all seven million citizens in 2003. If the smart card contains the full red cell phenotype/genotype of the ind ividual, it may be possible to transfuse phenotype-matched blood units with out pre-transfusion antibody screening. We conducted a feasibility study. Design and Methods. Red cell phenotype was determined for 407 donor blood u nits and 493 patients for whom an antibody screen had been ordered. The com puter program selected phenotype-matched blood from the donor stock for the patients according to actual transfusion request. For patients with a posi tive antibody screen, full crossmatching was carried out with the computer- selected phenotype units. The frequencies of the various red cell phenotype s in the population were calculated from Red Cross data of antigen frequenc ies. The probabilities of finding at least one unit of phenotype-matched bl ood from a 300-unit hospital stock and a 4,000-unit Red Cross stock were de termined for each phenotype. Cost analysis was performed. Results. Ninety-two out of 493 patients received a total of 395 blood units . The required number of phenotype-matched blood units could be found for 9 2 patients using a 300-unit pool and for all patients using a 4,000-unit po ol. We calculated that phenotype-matched blood could be provided for more t han 98% of patients without antibody screening, The total cost of the proje ct is US$ 98 million with potential savings of US$ 14 million per year. Interpretation and Conclusions. It is feasible and cost-effective to transf use patients with phenotype-matched blood without antibody screening using a smart card system. (C) 2001, Ferrata Storti Foundation.