Effect of agitation on the quality of platelet concentrates.

Platelet concentrates (PCs) were stored for 4 days at 22 degrees C in 400 ml second-generation (PL1240) platelet packs with either constant agitation, manual mixing once every 24 h or without agitation at any time. After 4 days storage, in vivo recovery, survival and biodistribution were determined following indium-111 labelling of platelets and infusion into autologous volunteers. In vitro assays of platelet function and biochemistry were likewise carried out after 4 days storage. The PCs stored without agitation had significantly lower in vivo recoveries, pH and aggregation responses to ionophore A23187 and a combination of collagen and epinephrine and significantly higher beta-thromboglobulin and indium-111 release than the agitated PCs. The manually mixed PCs were not significantly different from the constantly agitated PCs. PCs mixed simply once every 24 h remained viable with active oxidative phosphorylation and a pH above 6.74 in all but 1 case indicating that PCs stored at 22 degrees C for up to 4 days with only intermittent mixing are satisfactory for transfusion. A change from constant agitation would reduce capital costs in mixing equipment and simplify the transport of PCs from the transfusion centre to small hospital blood banks.