Maximising platelet availability by delaying cold storage

Background and ObjectivesCold-stored platelets may be an alternative to conventional room temperature (RT) storage. However, cold-stored platelets are cleared more rapidly from circulation, reducing their suitability for prophylactic transfusion. To minimise wastage, it may be beneficial to store platelets conventionally until near expiry (4 days) for prophylactic use, transferring them to refrigerated storage to facilitate an extended shelf life, reserving the platelets for the treatment of acute bleeding. Materials and MethodsTwo ABO-matched buffy-coat-derived platelets (30% plasma/70% SSP+) were pooled and split to produce matched pairs (n = 8 pairs). One unit was stored at 2-6 degrees C without agitation (day 1 postcollection; cold); the second unit was stored at 20-24 degrees C with constant agitation until day 4 then stored at 2-6 degrees C thereafter (delayed-cold). All units were tested for in vitro quality periodically over 21 days. ResultsDuring storage, cold and delayed-cold platelets maintained a similar platelet count. While pH and HSR were significantly higher in delayed-cold platelets, other metabolic markers, including lactate production and glucose consumption, did not differ significantly. Furthermore, surface expression of phosphatidylserine and CD62P, release of soluble CD62P and microparticles were not significantly different, suggesting similar activation profiles. Aggregation responses of delayed-cold platelets followed the same trend as cold platelets once transferred to cold storage, gradually declining over the storage period. ConclusionThe metabolic and activation profile of delayed-cold platelets was similar to cold-stored platelets. These data suggest that transferring platelets to refrigerated storage when near expiry may be a viable option for maximising platelet inventories.