Case report: solid-phase platelet crossmatching to support the alloimmunized patient

Platelet crossmatching by a solid-phase red cell adherence assay was used to provide compatible platelets for two alloimmunized patients with leukemia. In this study, a successful platelet transfusion was defined as giving a corrected count increment (CCI) of >7,500 in a posttransfusion sample. For patient A, a total of 205 random platelet concentrates (PCs) were crossmatched. Eleven were considered compatible. These 11 PCs were transfused during five transfusion episodes. Four of the five transfusions produced CCIs of >7,500 and were considered successful. Individually, eight of the eleven units were considered in vivo compatible, and five of the eight donors of these units agreed to become apheresis donors. Platelets from three of these five apheresis donors gave CCIs of >7,500. For patient B, 1,074 random PCs were crossmatched, and 332 were considered compatible. These units were administered during 78 different transfusions. Seventy-one of these transfusion episodes resulted in CCIs of >7,500. In addition, 19 apheresis donors were identified by platelet crossmatching, and they provided platelets for 38 of 39 successful transfusions for Patient B. Platelet crossmatching should therefore be considered when a blood bank is called upon to support a refractory thrombocytopenic patient.