Factors that influence platelet recovery after transfusion:: resolving donor quality from ABO compatibility

BACKGROUND: A system was established to examine the extent to which the apheresis donor determines platelet recovery after transfusion, to measure the impact of ABO identity, and to predict outcome by evaluating the donor. STUDY DESIGN AND METHODS: The percentage of platelet recovery was measured after prophylactic transfusion of apheresis units divided from single donors to paired recipients with uncomplicated thrombocytopenia secondary to leukemia chemotherapy. Platelet microaggregation induced by citrate was measured at the time of apheresis. RESULTS: Platelet recoveries in paired recipients correlated strongly when both transfusions were ABO-identical. When one recipient was ABO-identical and the other was ABO-non identical, nonidentical transfusions yielded one-third the recovery of ABO-identical transfusions. In ABO-identical transfusions, platelet recovery in donors having microaggregates in the before-apheresis ACD sample was one-third that in donors without microaggregates. This difference was observed at 1 and 24 hours. Expression of P-selectin in the apheresis units at the time of transfusion correlated well with ACD microaggregates in the before-apheresis sample. CONCLUSION: When transfusions of platelets are ABO-identical, donor quality dominates recovery in circulation. Donor quality is predicted by a rapid and simple assay of citrate-induced microaggregation performed at the time of apheresis. When donor quality is factored out, ABO identity prevails.