Effects of immediate or delayed addition of platelet additive solution on the in vitro quality of apheresis platelets.

BACKGROUND: There is little knowledge how different hold times of hyperconcentrated platelet (PLT) suspensions (HPSs) before the addition of platelet additive solution (PAS) might affect PLT quality. We compared the in vitro quality of single-donor PLT concentrates (SDPs) with immediate or delayed PAS addition and studied the quality of collected concurrent plasma (CP). STUDY DESIGN AND METHODS: We collected 6 x 1011 PLTs in 175 of mL plasma and CP from 31 donors. The HPSs were split into two parts, with 162 mL of modified PAS III (PAS-IIIM) added immediately (0hr-SDP) or 2 hours later (2hr-SDP). Final SDPs had a targeted concentration of 1.2 x 1012 PLTs/L and a PAS proportion of 65%. On Days 1, 5, and 7 we determined glucose and lactate concentration, pH, P-selectin expression, hypotonic shock response (HSR), and extent of shape change (ESC). Clotting Factor V (FV) and VIII (FVIII) activities and D-dimer concentration were determined in CP and donor. RESULTS: Glucose utilization, lactate production, and pH were similar for both kinds of products. Low P-selectin expression indicated no relevant PLT activation during storage. HSR and ESC were similarly well preserved. Recoveries of FV and FVIII were 100.0 +/- 14.0 and 98.6 +/- 14.9%, respectively. Concentrations of D-dimers in the donor and CP were 173.7 +/- 90.1 and 177.6 +/- 91.2 ng/dL, respectively. CONCLUSIONS: Adding PAS immediately or 2 hours after collection does not result in different in vitro quality of PLTs stored up to 7 days. The good recovery of clotting factors with no signs of activation indicates a good quality of CP.