Clinical Report: 21-day cold-stored platelets may maintain hemostasis

Overview

In the phase 3 CHIPS trial, cold-stored platelets met the prespecified noninferiority criterion for hemostatic efficacy compared with room-temperature platelets at every evaluated storage duration through 21 days in patients undergoing cardiac surgery with cardiopulmonary bypass. Chest tube output did not differ significantly, but exploratory analyses found more reexplorations for bleeding and greater blood-product use in the cold-stored group.

Background

Platelets are conventionally stored at room temperature, while cold storage may offer an alternative for platelet availability and use. CHIPS evaluated cold-stored platelets in pediatric and adult patients undergoing complex cardiac surgery with planned cardiopulmonary bypass and anticipated bleeding requiring platelet transfusion. In the United States, FDA guidance permits apheresis cold-stored platelets at 1°C to 6°C for up to 14 days for active bleeding when conventional platelets are unavailable or impractical; it does not extend use to 21 days or prophylaxis. The 2025 AABB/ICTMG guideline recommends against platelet transfusion in nonthrombocytopenic patients undergoing cardiovascular surgery without major hemorrhage.

Data Highlights

Key Findings

• CHIPS was a multicenter, randomized, partially blinded, adaptive noninferiority trial conducted at 27 sites in the United States and Australia from December 2021 to March 2025.
• Of 1,811 randomized patients, 1,000 received platelet transfusions; the primary efficacy analysis included 989 patients.
• Cold-stored platelets met the prespecified noninferiority criterion at every evaluated storage duration through 21 days, with posterior probability exceeding 99.9%; no duration demonstrated superiority over conventional storage.
• There was no statistically significant difference in 24-hour chest tube output, and prespecified subgroup analyses showed consistent noninferiority across evaluated patient groups.
• Reexploration for bleeding within 24 hours occurred in 4.2% of cold-stored platelet recipients and 1.8% of room-temperature platelet recipients; the cold-stored group also received greater volumes of several blood products at 24 and 72 hours after ICU admission.
• Exploratory safety analyses found no statistically significant between-group differences in thrombotic events, transfusion-associated adverse events, acute respiratory distress syndrome, kidney failure, septic shock, or mortality. The authors noted that nonstandardized transfusion indications and some patients receiving both platelet types could have favored noninferiority.

Clinical Implications

The trial supports noninferior hemostatic efficacy of cold-stored platelets through 21 days in the studied cardiac-surgery population, while exploratory findings of more reexploration and greater blood-product use warrant consideration when interpreting the results. Current US FDA guidance described in the source permits cold-stored platelets for active bleeding for up to 14 days when conventional platelets are unavailable or impractical; the trial's 21-day findings do not themselves establish regulatory authorization for that duration.

Conclusion

In CHIPS, cold-stored platelets maintained noninferior hemostatic efficacy compared with room-temperature platelets through 21 days of storage. This finding coexisted with higher observed reexploration and blood-product use in the cold-stored group, and the trial authors identified limitations that may have favored noninferiority.

Related Resources & Content

1. CHIPS investigators, JAMA, 2026 — Cold and Room-Temperature Platelets in Cardiac Surgery: The CHIPS Randomized Clinical Trial
2. US Food and Drug Administration, 2023 — Alternative Procedures for the Manufacture of Cold-Stored Platelets Intended for the Treatment of Active Bleeding when Conventional Platelets Are Not Available or Their Use Is Not Practical; Guidance for Industry
3. AABB and ICTMG, JAMA, 2025 — Platelet Transfusion: 2025 AABB and ICTMG International Clinical Practice Guidelines
4. ASCO Publications — Non-inferiority of a new advanced dry plasma thawing system compared to leading standard method: Preservation of coagulation and anticoagulation proteins necessary for use in the clinic.
5. ASCO Publications — Non-inferiority of a new advanced dry plasma thawing system compared to leading standard method: Preservation of coagulation and anticoagulation proteins necessary for use in the clinic.
6. Frontiers in Medicine — Minimal bacterial contamination observed in platelet components after primary culture assessment: insights from Saudi Arabia
7. Bone Marrow Transplantation — A chemically defined, bioinspired substitute for dimethyl sulfoxide in the cryopreservation of human hematopoietic stem cells
8. Cold and Room-Temperature Platelets in Cardiac Surgery: The CHIPS Randomized Clinical Trial
9. FDA Guidance: Alternative Procedures for the Manufacture of Cold-Stored Platelets
10. Platelet Transfusion: 2025 AABB and ICTMG International Clinical Practice Guidelines
11. Alternative Procedures for the Manufacture of Cold-Stored Platelets Intended for the Treatment of Active Bleeding when Conventional Platelets Are Not Available or Their Use Is Not Practical; Guidance for Industry
12. Platelet Transfusion: 2025 AABB and ICTMG International Clinical Practice Guidelines | Bleeding and Transfusion | JAMA | JAMA Network
13. Cryopreserved vs Liquid-Stored Platelets for the Treatment of Surgical Bleeding: The CLIP-II Randomized Noninferiority Clinical Trial | Cardiothoracic Surgery | JAMA | JAMA Network
14. Early Cold Stored Platelet Transfusion Following Severe Injury: A Randomized Clinical Trial - PMC