Pooled platelet concentrates (PC) prepared by the platelet-rich plasma (PRP) method were filtered with three different filters and stored for 8 days at room temperature. The effect of filtration on leukocyte contamination, platelet concentration, and the in vitro function, morphology, metabolism and activation of platelets were studied. Eight pools of 20 PRP-PC were used, each pool was split into 4 equal volumes; 3 were filtered over a PL50HF, a PL-10A and a Bio PIO filter, the 4 served as a control. After filtration, leukocyte counts exceeded 3x10^5 in none of the pooled PC. Platelet loss induced by filtration was about 17%. During storage, no differences in pH, PC02, and lactate and glucose concentration were found between the filtered and the unfiltered units, nor were any differences observed between filtered and unfiltered pooled PC in aggregation upon stimulation with collagen and/or ADP, adhesion capacity to collagen in flowing blood, nucleotide content of the platelets and nucleobase concentration in the plasma, expression of activation-dependent antigens, or platelet morphology as observed by light microscopy and by the swirling effect. Selective removal of β-thromboglobulin (22%) by the PL50HF filter was observed. Pooled PC prepared by the PRP-method can be filtered and stored for 8 days without detrimental effect on platelet function, metabolism or activation.

Platelet concentrates (PC) were stored for 6 days in either polyolefin (PO) or polyvinylchloride/di-(2-ethylhexyl)phtalate (PVC/DEHP) bags in 100% plasma or in a synthetic medium with 35 or 10% plasma. For all conditions studied the usual in vitro parameters were well maintained, with a pFI above 6.8. In both bag types platelets can be satisfactorily stored for 6 days in a synthetic medium with minimal amounts of residual plasma. For this medium, the PO bag offers a slight advantage with respect to the preservation of platelet ATP content (>80 versus >70% in the PVC bags) and aggregation and adhesion capacity. The adhesion capacity increased in the PO bags, while it decreased in the PVC bags.