Retrospective cohort studies of repeat donors reveal donor-dependent variability in the recovery of transfused platelets.

<bold>Background: </bold>The in vivo recovery of transfused platelets is variable and often unpredictable. Although many recipient-dependent factors are well described, donor-dependent variables remain poorly understood.<bold>Study Design and Methods: </bold>To explore donor-dependent variables we conducted 2 retrospective studies of platelet transfusion outcomes in repeat donors. One study analyzed multiple autologous, radiolabeled platelet transfusions, and a second study analyzed multiple clinical platelet transfusions from a small cohort of repeat donors.<bold>Results: </bold>In 36 subjects, multiple within-subject determinations of recovery and survival of radiolabeled autologous platelets revealed a relative consistency in platelet recoveries within donors compared to the range of recoveries among donors. Intraclass correlation coefficients for platelet recovery were 43% to 93%. In 524 ABO-compatible clinical platelet transfusions derived from seven donors, a linear mixed-effects model revealed significant donor-dependent differences in corrected count increments for units stored for 4 or 5 days.<bold>Conclusions: </bold>These two studies indicate reproducible donor-dependent differences in transfused platelet recovery, suggesting a possible heritable influence on the quality of transfused platelets. [ABSTRACT FROM AUTHOR]