Soleil Research | Evidence Review
A major practical limitation in transfusion medicine is the short shelf life of conventional room-temperature platelets. The newly published CHIlled Platelet Study (CHIPS), a phase 3 randomized clinical trial in JAMA, tested whether platelets stored cold for as long as 21 days could maintain hemostatic efficacy in patients with active bleeding during cardiac surgery. The answer was encouraging—but narrower than a headline such as “cold platelets are better” would suggest.
Plain-Language Summary
In the CHIPS trial, 1,000 adult and pediatric patients who required platelet transfusion for active bleeding during cardiac surgery with cardiopulmonary bypass were randomized to cold-stored platelets or standard room-temperature platelets. Cold-stored platelets kept for up to 21 days met the trial’s prespecified criterion for noninferiority in controlling bleeding. Twenty-four-hour chest-tube output was also similar between groups. Most reported safety outcomes did not differ, but surgical reexploration was increased in the cold-stored platelet group. The trial therefore supports longer cold storage for this specific bleeding setting, while leaving important questions about safety, implementation, and use in other patient populations.
Why This Study Matters
Standard platelets are usually stored at 20–24 °C for approximately 5 to 7 days. That narrow storage window creates logistical pressure for blood centers and hospitals because platelet demand is difficult to predict and expired units are discarded. Cold storage at 1–6 °C could potentially extend usable shelf life and improve inventory resilience, especially where platelet access is limited.
The key clinical question is not simply whether cold storage preserves laboratory characteristics. It is whether cold-stored platelets remain sufficiently effective and acceptably safe when transfused to patients who are actively bleeding. CHIPS was designed to address that question directly.
What CHIPS Tested
CHIPS was a phase 3, multicenter, randomized, partially blinded, adaptive noninferiority trial conducted at 27 sites in the United States and Australia. Adult and pediatric patients undergoing cardiac surgery with planned cardiopulmonary bypass who developed active bleeding requiring platelet transfusion were randomized 2:1 to receive cold-stored platelets, with storage durations extending to 21 days, or room-temperature platelets stored for up to 7 days.
The primary outcome was a hemostatic efficacy score ranging from 1 to 5, with higher scores representing greater bleeding. The prespecified noninferiority margin was 1 point. To meet the trial’s success criterion, at least one cold-storage duration of 7 days or longer had to achieve a posterior probability of noninferiority of at least 97.5%. The principal secondary outcome was chest-tube output at 24 hours.
What the Trial Found
Of the 1,000 participants who received platelet transfusion, 989 were included in the primary analysis: 650 in the cold-stored platelet group and 339 in the room-temperature group. Every evaluated cold-storage duration achieved a posterior probability of noninferiority greater than 99.9%. When storage durations were pooled, the mean difference in hemostatic efficacy score between cold-stored and room-temperature platelets was 0.09, with a 95% credible interval from −0.06 to 0.23.
Twenty-four-hour chest-tube output was 8.9 mL/kg (IQR, 5.2–15.4) with cold-stored platelets and 8.4 mL/kg (IQR, 5.5–15.9) with room-temperature platelets. The difference in medians was 0.4 mL/kg (95% CI, −1.0 to 1.5), and the groups were not statistically different on this outcome.
The trial reported no differences between groups in venous or arterial thrombotic events, transfusion-associated adverse events, acute respiratory distress syndrome, kidney failure, septic shock, or mortality. However, reexploration was increased in the cold-stored platelet group. Because the accessible abstract does not provide the event counts for this signal, Soleil Research does not quantify or minimize it; it should remain part of the safety interpretation.
Methodological Quality
Overall assessment: high quality for the primary hemostatic-efficacy question, with important limits for broader safety and generalizability.
The study’s major methodological strengths are its randomized phase 3 design, large sample, multicenter enrollment, inclusion of both adult and pediatric cardiac-surgery populations, direct comparison with the current standard platelet-storage strategy, and an adaptive design specifically constructed to evaluate storage duration through 21 days. The trial also used a prespecified Bayesian noninferiority framework and included a quantitative secondary measure of postoperative bleeding.
Several features require disciplined interpretation. First, this was a noninferiority trial. Demonstrating noninferiority within a 1-point margin does not establish equivalence or superiority. Second, the trial was partially rather than fully blinded. Third, the primary endpoint was an ordinal hemostatic efficacy score rather than mortality or a single purely objective clinical endpoint. Fourth, the 2:1 randomization produced a smaller control group. Eleven transfused participants were not included in the primary analysis. Finally, uncommon adverse events may require larger datasets or postimplementation surveillance to characterize reliably.
Strengths
CHIPS addresses a clinically and operationally important question using a strong experimental design. The trial was large, international, multicenter, randomized, and conducted in patients with actual surgical bleeding rather than only in vitro systems or healthy volunteers. Its storage-duration-ranging approach is particularly valuable because it tests the practical question of how long cold-stored platelets may remain clinically useful, rather than treating refrigeration as a single binary exposure.
Limitations and Cautions
The findings should not be generalized automatically beyond the population studied. CHIPS evaluated patients with active bleeding during cardiac surgery involving cardiopulmonary bypass. It does not establish comparable efficacy for prophylactic platelet transfusion, hematologic malignancy, trauma, obstetric hemorrhage, or other settings. The observed increase in reexploration also deserves further analysis rather than being dismissed because most other safety outcomes were similar.
Operational advantages should likewise be separated from clinical efficacy. A 21-day storage window could plausibly reduce wastage and improve availability, but the trial’s primary finding was hemostatic noninferiority—not proof that a cold-storage inventory strategy will reduce costs, eliminate shortages, or improve patient outcomes across health systems.
Funding and Conflicts of Interest
The peer-reviewed CHIPS design publication reported that the trial was funded through a contract from the U.S. Army Medical Research and Development Command via the U.S. Army Medical Research Acquisition Activity. That design paper also disclosed that Roger J. Lewis was a senior medical scientist at Berry Consultants and that Berry Consultants was compensated for his work related to trial design, implementation, and oversight; Nicholas S. Berry was an employee of Berry Consultants. Both Lewis and Berry are authors of the 2026 JAMA trial report.
The publicly accessible JAMA abstract page available for this review does not expose the full conflict-of-interest disclosure section for the final 2026 article. For that reason, Soleil Research does not assume that the disclosures in the earlier design paper are identical to the final JAMA disclosures. Readers conducting regulatory, policy, or formal evidence reviews should consult the complete JAMA disclosure statement directly.
Soleil Insight
The important result is not that cold-stored platelets are “better.” It is that, in this specific cardiac-surgery bleeding context, extending cold storage to 21 days did not produce a clinically meaningful loss of hemostatic efficacy under the trial’s prespecified noninferiority framework. That could be important for platelet access and inventory management. But noninferiority is not superiority, the reexploration signal warrants attention, and the findings should not be extrapolated indiscriminately to prophylactic transfusion or other clinical settings.
For transfusion medicine, the study is a strong example of how operational innovation should be evaluated: not by assuming that longer shelf life is beneficial, but by testing whether the product still performs adequately where patient outcomes matter.
Original Publication
Spinella PC, Zantek ND, VanBuren JM, et al; for the CHIPS Investigator Group. Cold and Room-Temperature Platelets in Cardiac Surgery: The CHIPS Randomized Clinical Trial. JAMA. Published online August 17, 2026. doi:10.1001/jama.2026.13328. Trial registration: NCT04834414.
View the original JAMA publication
Featured image: NIH/NIAID BioArt platelet illustration, courtesy of Ryan Kissinger; public-domain U.S. Government work.
Advancing Science. Empowering Humanity.
Soleil Research provides evidence-focused scientific education and does not replace clinical judgment, institutional policy, or professional medical guidance.