Race-related red cell alloantibody problems.

Some years ago differences in red cell blood group phenotypes among individuals of different ethnic backgrounds were of little moment to blood transfusion services. This was because in many instances the ethnic group of the majority of patients closely matched that of the donor pool. The dramatic population movements of the last 20-30 years have changed this situation. Now it is not uncommon for a transfusion service whose donors are primarily European Caucasian in ancestry to be required to supply blood for patients, a substantial proportion of whom are of Black or Oriental extraction. This problem affects the donor service in terms of supply and demand, and both the donor service and hospital transfusion service in terms of antibody identification. In this paper some aspects of this problem are explored and illustrations are given of how knowledge of an antibody-maker's ethnic background can sometimes be used to accelerate identification of an antibody, particularly one directed against a very common antigen. The effects of differences in antigen frequency are also considered in terms of long-term transfusion support of some patients.