Influence of storage temperature on the responsiveness of human platelets to agonists.

To investigate the effects of storage temperature on the responsiveness to agonists of human platelets prepared from stored blood, we measured the aggregability and acid-base status of platelets from 96 healthy subjects before and after storage of whole blood at 4 degrees C and room temperature (RT) up to 48 hr. After 24 hr storage at 4 degrees C, there were no significant differences in agonist-induced platelet aggregability, compared to fresh specimens. When blood was kept at RT for 24 hr, all of the platelet samples showed non-responsiveness (< 20% aggregability) to epinephrine and 70% (67/96) revealed impaired responsiveness (20 to 60% aggregability) to adenosine diphosphate (ADP); there were no samples that showed impaired- or non-responsiveness to collagen or ristocetin. Among the 67 samples that showed impaired responsiveness to ADP after RT storage, 62 (93%) exhibited the loss of a secondary wave of aggregation in response to ADP. After storage of blood at RT for 48 hr (pH 6.81 +/- 0.06), mean values of maximal platelet aggregability to epinephrine, ADP, collagen, and ristocetin were 8%, 16%, 19%, and 70%, which were significantly lower than the corresponding mean values after storage of blood at 4 degrees C for 48 hr (pH 7.04 +/- 0.04) (ie, 66%, 69%, 102%, and 91%, p < 0.01). In summary, refrigerated storage of human blood improves the stability of platelet responsiveness to agonists. Storage at RT causes platelet non-responsiveness to epinephrine and disturbs the release reaction of endogenous ADP.