Delaying refrigeration of platelets for several days after collection appeared to preserve their function long enough to remain useful through day 10, according to a study published recently in Vox Sanguinis.
These findings that may directly affect transfusion strategies for patients with conditions such as fetal and neonatal alloimmune thrombocytopenia (FNAIT), where timely access to effective platelets is critical.
In FNAIT, a rare condition in which a mother’s immune system attacks a fetus or newborn’s platelets, transfusions are often lifesaving. Platelet storage limitations can restrict availability. This study evaluated whether changing when platelets are cooled could safely extend their usability without compromising performance.
Researchers in Japan examined apheresis-derived platelets stored in an additive solution and divided them into three groups based on when refrigeration began: immediately on day zero, after two days at room temperature or after five days. All units were stored up to day 21 and assessed for clotting ability, aggregation and activation markers.
“Although substantial evidence for the utility of cold-stored PLTs [platelets] has been accumulated and the associated challenges have been increasingly clarified, information on the clinical utility of delayed cold-stored PLTs remains limited,” explained the authors of this study.
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Through day 14, most platelet characteristics remained stable across all groups. Only two measures, adenosine diphosphate plus collagen–induced aggregation and maximum clot firmness, declined modestly in the delayed cooling groups. However, by day 10, these values were still comparable to platelets refrigerated immediately and assessed at day 14, which aligns with current US expiration standards.
Other indicators, including platelet count, pH and key activation markers such as CD62P, PAC-1 and Annexin V, showed no meaningful differences between groups through at least day 10. Ristocetin-induced aggregation, another measure of platelet function relevant to clot formation, also remained stable through day 14 regardless of storage timing.
For patients with FNAIT and other bleeding disorders, these findings suggest that platelet units stored at room temperature for a short period before refrigeration could remain clinically effective for transfusion longer than previously assumed. This may improve inventory flexibility, reduce waste and increase access to compatible platelets in urgent situations.
While further clinical validation is needed, the results indicate that delayed cold storage does not significantly impair platelet quality in the short term. For patients and families affected by FNAIT, this could translate into more reliable access to life-saving transfusions when timing is most critical.
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