Compatibility testing between the blood of donors and recipients in Nigerians

5163 consecutive units of group O donor blood or donor blood of the same ABO and Rh (D) blood group as the recipient (patient) crossmatched for 2500 patients between 1981 and 1983 were analysed for the occurrence of incompatibility due to agglutinating antibodies. A surprisingly low percentage (1.76%) of all the donor/recipient crossmatches were incompatible, with the frequency of incompatibility being 1.83% when the donors are of same blood group as the recipients (intra-group crossmatches) compared to a frequency of incompatibility of 0.7% when group O donors are crossmatched for group A, B or AB recipients or group A or B donors are crossmatched for group AB patient (inter-group crossmatches). There were only 5 out of 2500 recipients (0.2%) with positive "Auto Control' against whom 16 units of donor blood were unsuccessfully cross matched. Contrary to popular belief, the uses of Group O as a "universal donor' was very infrequent, involving only 225 out of 5163 (4.35%) donor units. The clinical significance of these findings are discussed and explanations are offered.