Downscaling to small‐volume storage bags supports platelet quality and efficient use of cold‐stored platelets for preclinical studies

Background To maximize the utilization of cold‐stored platelets (CSPs) in preclinical research, the use of small‐volume storage bags (mini‐bags) or tubes would allow multiple treatment groups to be investigated from a single component. It is necessary to determine the effect of using downscaled storage formats on CSP quality and function. Methods Mini‐bags were prepared by vacuum sealing platelet storage bags to ¼ the standard size. Apheresis platelets ( n = 8) in 40% plasma/60% PAS‐E (SSP+) were aseptically aliquoted into mini‐bags (30 mL) or polypropylene tubes (15 mL; CSP‐tubes), and the remaining volume (~190 mL) was retained in the original bag (control). Platelets were refrigerated (2–6°C), and in vitro quality parameters were assessed over 21 days. Results Metabolic capacity was altered for CSP‐tubes, with a significant decline in pH, mitochondrial membrane depolarization, and rapid glycolysis. CSP‐tubes had greater storage‐related activation, as evidenced by a higher proportion of annexin‐V‐positive platelets and a greater number of CD61+/annexin‐V+ extracellular vesicles (EVs). Similarly, platelet functional capacity in CSP‐tubes was compromised, with reduced clot strength compared to controls. CSPs stored in mini‐bags remained comparable to controls, with the exception of a greater proportion of annexin‐V‐positive platelets and EVs at day 21. Importantly, despite these changes, no functional deficits were observed in mini‐bag components. Conclusions Storage in tubes markedly impairs the metabolic, structural, and functional quality of CSPs, indicating that this approach is unsuitable. In comparison, mini‐bag storage preserves key in vitro parameters, supporting a scalable strategy that maximizes the utilization of CSPs for preclinical evaluation.