In vitro characteristics of white cell-reduced single-unit platelet concentrates stored in syringes

BACKGROUND: Platelet concentrates (PCs) for premature infants may be subjected to filtration, centrifugation, and various storage conditions before transfusion. STUDY DESIGN AND METHODS: As there are few data on the cumulative effect of these procedures on PCs, platelet properties (including biochemical and functional in vitro assays) were evaluated after the processing of single units of PCs through a 1-unit-capacity high-efficiency white cell (WBC)-reduction filter followed by syringe storage at either 22 or 37 degrees C for 6 hours. Two- and 5-day-old PCs, volume-reduced PCs, and prestorage WBC-reduced PCs were evaluated. RESULTS: WBC filtration consistently resulted in a 3 to 4 log10 reduction in WBCs, with less than 15-percent platelet loss. No adverse effects of platelet function or evidence of increased platelet activation as determined by the percentage of P-selectin positivity were noted. A decrease in pH associated with increased lactate production and consumption of glucose was observed following syringe storage under all conditions tested. Such changes were most pronounced, however, with volume-reduced PCs stored at 37 degrees C (pH 6.31 +/− 0.15, lactate 23.0 +/− 3.06 mmol/L). All pH levels at the end of storage were above the minimum Food and Drug Administration requirement (pH 6.0). CONCLUSION: The in vitro data suggest that single units of PCs can undergo WBC filtration followed by syringe storage for up to 6 hours and still maintain acceptable storage characteristics. The practice of maintaining volume-reduced PCs in syringes for 6 hours at 37 degrees C in isolettes during transfusion should, however, be avoided.