A randomized controlled trial comparing autologous radiolabeled in vivo platelet (PLT) recoveries and survivals of 7-day-stored PLT-rich plasma and buffy coat PLTs from the same subjects

BACKGROUND: A recent review concluded that there was inadequate evidence to show a difference between buffy coat (BC) and platelet (PLT)-rich plasma (PRP) PLT concentrates prepared from whole blood. We hypothesized that 7-day-stored BC-PLTs would have superior autologous recoveries and survivals compared to PRP-PLTs and that both would meet the Food and Drug Administration (FDA) criteria for poststorage viability. STUDY DESIGN AND METHODS: This was a randomized, crossover study design in healthy subjects who provided informed consent. Each participant donated a unit of whole blood on two occasions. In random order, either BC-PLTs or PC-PLTs were prepared after a 20 +/- 2 degrees C overnight hold of the whole blood. PLTs were stored under standard conditions. On Day 7, fresh PLTs were prepared from 43 mL of autologous whole blood. The fresh PLTs paired with either BC-PLTs or PRP-PLTs were alternately labeled with In-111 or Cr-51 and simultaneously reinfused to determine recoveries and survivals. In vitro assays were performed on Days 1 and 7. RESULTS: Fourteen subjects completed the study at two sites. No differences in poststorage PLT viabilities were observed between BC-PLTs and PRP-PLTs; recovery differences averaged 3.7 +/- 2.4% (+/- SE, p = 0.15) and survival differences averaged 0.48 +/- 0.56 days (p = 0.41). Neither type of PLTs met the current FDA criteria for either poststorage PLT recoveries or survivals. CONCLUSION: We were unable to demonstrate that single-unit BC-PLTs stored for 7 days have superior poststorage viability compared to PRP-PLTs. Failure to meet the minimum FDA criteria for poststorage PLT viability raises questions regarding the acceptance thresholds of these metrics.