Rh and Kell Phenotype Matched Blood Versus Randomly Selected and Conventionally Cross Matched Blood on Incidence of Alloimmunization

There is paucity of literature regarding efficacy of transfusion of Rh and Kell matched blood in reducing alloimmunization risk among non-chronically transfused patients. A prospective study to compare efficacy of Rh and Kell phenotype matched blood over randomly selected and conventionally cross-matched blood on the incidence of alloimmunization in patients undergoing cardiac surgery was carried out in the Department of Transfusion Medicine at Indraprastha Apollo Hospitals, New Delhi, from 1st September, 2013 to 31st December, 2014. Two groups, A and B of 250 each were studied. Group A received ABO, Rh and Kell phenotype matched units. Group B received units matched only for ABO and Rh D. Retrospective analysis for antigenic exposures was done. Alloimmunization rate was evaluated for both groups after 72 h and 4 weeks and compared. A p value ≤0.05 was considered statistically significant. None of the patients in Group A were alloimmunized. In Group B, 119 patients received antigenic stimulus (single antigen stimuli- 93; multiple- 26). The probability of a patient being exposed was 52.4 %. At 6 weeks post transfusion, one patient developed ‘Anti-E’ and had received ‘E’ stimulus once. The rate of alloimmunization was 0.4 % in group B, 0.8 % overall and the risk of alloimmunization per unit transfused was 0.17 %. Non responders were 99.16 %. The study did not reach statistical significance (p = 0.238). Majority of our population are non-responders therefore, the resources and time can be reserved for providing Rh and Kell matched units for multiply transfused patients.