A new study published in JAMA reports that cold-stored platelets may be just as effective as conventional room-temperature platelets for controlling active bleeding during cardiac surgery, potentially challenging one of the most persistent assumptions in transfusion medicine. The investigation found that cold-stored platelets, or CSPs, kept at temperatures substantially below those used for standard room-temperature platelet products were noninferior to room-temperature platelets, commonly called RTPs, when used to treat surgical bleeding. The finding could have immediate implications for hospitals facing platelet shortages, high rates of product wastage, and the logistical difficulties of maintaining a fragile blood product with a short shelf life.
Platelets are small, disk-shaped blood cells that circulate through the bloodstream and rapidly respond when blood vessels are damaged. They adhere to injured tissue, become activated, change shape, and recruit additional platelets to form an initial plug. They also provide a surface on which coagulation reactions can occur, helping generate fibrin, the protein mesh that stabilizes a clot. During cardiac surgery, however, this system is placed under extreme stress. Cardiopulmonary bypass can dilute circulating blood components, alter platelet function, and expose blood to artificial surfaces. Surgical trauma, anticoagulant medications, and the effects of hypothermia can further disrupt clot formation, making platelet transfusion a critical intervention when bleeding becomes difficult to control.
For decades, standard platelet concentrates have generally been stored at controlled room temperature with continuous agitation. This approach preserves certain aspects of platelet biology, including the ability to circulate and function after transfusion, but it also creates a significant safety and supply challenge. Warm storage permits the growth of bacteria if contamination occurs, which is why room-temperature platelets typically have a shelf life of only five to seven days, depending on regulatory and institutional requirements. Every day that passes reduces the remaining usable window, and units that are not transfused before expiration must be discarded. The short shelf life makes platelet inventories particularly vulnerable during emergencies, transportation disruptions, severe weather, and sudden surges in demand.
Cold storage changes the biology of platelets. Refrigeration slows cellular metabolism and may reduce the risk of bacterial proliferation, allowing the products to be held for substantially longer periods. At the same time, exposure to cold can cause platelets to undergo changes in their membrane structure and surface receptors. These alterations may reduce their circulation time after transfusion, meaning that they may not remain in the bloodstream as long as room-temperature platelets. For patients with active bleeding, however, immediate clot-forming performance may be more important than prolonged circulation. Cold-stored platelets can display enhanced activation and increased adhesive behavior, characteristics that could make them particularly useful in situations where rapid hemostasis is required.
The JAMA investigation focused on patients undergoing cardiac surgery, a population in which bleeding can develop abruptly and require large quantities of blood components. The central question was not whether the two platelet products were biologically identical, but whether cold-stored units could control active surgical bleeding at least as effectively as conventional room-temperature units. In clinical research, a noninferiority result means that the newer or alternative treatment did not perform worse than the established treatment by more than a prespecified clinically acceptable margin. That distinction is important: the study does not necessarily prove that cold-stored platelets are superior in every circumstance, but it supports their use as an effective alternative for the specific bleeding context evaluated.
The potential benefits extend beyond the operating room. A platelet product that can be stored for up to 21 days could provide hospitals with a larger operational buffer than conventional products. Instead of relying on frequent deliveries and carefully synchronized transfusion schedules, blood banks could maintain reserve supplies for urgent cases. Longer storage could also make it practical to stock platelets in smaller or remote hospitals that cannot reliably maintain a rotating five- to seven-day inventory. In rural facilities, trauma centers, military medical units, and disaster-response settings, the ability to hold platelets for weeks could transform emergency preparedness by reducing dependence on immediate access to a regional blood center.
The longer shelf life could also reduce wastage, although the degree of improvement would depend on how hospitals deploy the products. Platelet waste occurs when units expire, are damaged, or cannot be used before their storage limit. Because platelet production depends on volunteer donors and complex collection systems, each discarded unit represents both a lost medical resource and a lost donation opportunity. Cold storage could permit institutions to order products less frequently, retain reserve units for unpredictable bleeding events, and move supplies between facilities without the same pressure created by rapid expiration. In an era of persistent blood shortages, these logistical advantages may be nearly as important as the clinical findings.
The study’s implications must nevertheless be interpreted within its clinical boundaries. Cardiac surgery involves a distinctive pattern of bleeding, and the performance of cold-stored platelets in other settings may differ. Patients with trauma, intracranial hemorrhage, hematologic disorders, or prolonged medical bleeding may require separate evidence. The shorter circulation time associated with refrigerated platelets could matter when transfused prophylactically or when patients need sustained platelet support rather than rapid control of an acute surgical hemorrhage. Blood banks will also need validated procedures for collection, labeling, transportation, quality monitoring, and integration with existing transfusion protocols before widespread adoption becomes routine.
The findings arrive as transfusion specialists seek ways to make blood systems more resilient without compromising patient safety. Platelet products are among the most difficult components to manage because they are perishable, expensive to produce, and essential in the moments when bleeding becomes life-threatening. A 21-day cold-storage strategy could create a more flexible inventory, improve access in locations with limited blood-bank infrastructure, and reduce the number of usable units lost to expiration. If future studies confirm the results across trauma, transplantation, and other high-risk settings, refrigerated platelets could move from a niche option to a central part of emergency transfusion practice. For now, the cardiac-surgery evidence offers a powerful signal that the traditional room-temperature model may not be the only safe and effective way to preserve these indispensable clot-forming cells.
Subject of Research: Cold-stored platelets compared with room-temperature platelets for controlling active bleeding during cardiac surgery.
Web References: https://doi.org/10.1001/jama.2026.13328
References: Spinella PC et al., JAMA, DOI: 10.1001/jama.2026.13328.
Keywords
Platelets, cold-stored platelets, room-temperature platelets, cardiac surgery, surgical bleeding, transfusion medicine, blood inventory, platelet storage, blood shortages, medical waste, cardiology, surgery, thermodynamics, hemostasis.
Tags: artificial surface impact on blood componentsblood product shortagescardiac surgery bleeding controlcold-stored plateletshypothermia effects on clottingnoninferiority of cold-stored plateletsplatelet function in surgeryplatelet product wastage reductionplatelet shelf life and logisticsplatelet storage methodsroom-temperature platelet efficacytransfusion medicine advancements
