INCIDENCE OF ANTI-WRA DETECTION USING WR(A+) ANTIBODY SCREENING CELLS IN PRE-TRANSFUSION TESTING

Background and Objectives Antibodies to low incidence RBC antigens are not rare in candidates to blood transfusion, though the risk of receiving a non-compatible unit is low. Sometimes commercial RBC sets for the screening of irregular antibodies contain Wr(a+) cells: but these cells increase the workload of antibody characterization due to the presence of anti-Wra in recipients. Materials and Methods We have studied both the incidence of Wra antibodies and the effects on routine work of having a Wr(a+) cell in the screening test in an unselected population of 787 patients requiring RBC transfusion and in 151 new blood donors. Results Irregular antibodies were found in 64 sera, 58 of which were specific for Wra , 46 (5,8%) and 12 (7,9%) among patients and donors, respectively. All the positive tested sera contained specific IgM, whereas IgG were also found in 71% of the cases. The use of an antibody screening RBC set, including a Wr(a+) cell, increased the efforts towards the definition of the irregular Abs in the positive screened samples, by three times compared to the previous period. Conclusion A specific anti- Wra IgM component has always been found in positive sera. This component can easily be detected during cross- match procedures. Moreover, the association between anti-Wra and haemolytic transfusion reaction is rare. Therefore, the inclusion of Wr(a+) cells in pre-transfusion screening of blood recipients is not justified by clinical relevance and it causes an undue increase in costs and time to unit release.