8/17/2026
A Pitt-led trial found refrigerated platelets stored for up to 21 days controlled bleeding as well as standard platelets stored for seven days.
PITTSBURGH — A University of Pittsburgh School of Medicine-led clinical trial found that platelets refrigerated for up to 21 days controlled bleeding as effectively as standard room-temperature platelets stored for up to seven days. The findings, published Aug. 17, 2026, in JAMA, could triple to quadruple the usable U.S. platelet supply.
Key Takeaways
- The Pitt-led CHIPS trial found that platelets refrigerated for up to 21 days were as effective at controlling bleeding as standard room-temperature platelets stored for up to seven days.
- The trial enrolled 1,000 pediatric and adult patients undergoing cardiac surgery at 27 sites in the U.S. and Australia from December 2021 to March 2025, with roughly a third of participants being children.
- Results, published in JAMA and led by Philip Spinella, M.D., of Pitt's School of Medicine, are under consideration by the FDA and other countries weighing revised regulations for cold-stored platelets.
- Extending platelet shelf life to 21 days could nearly quadruple usable supply, addressing waste that costs U.S. hospitals an estimated $300 million a year, according to recent research.
- Vitalant, which supplied platelets for the study, reported that about 15% of hospitals experience at least one delayed platelet transfusion per month due to supply shortages.
The Chilled Platelet Study, known as CHIPS, is an adaptive clinical trial that compared cold-stored platelets — platelets kept refrigerated rather than at room temperature — with standard platelets in patients having heart surgery. Researchers enrolled 1,000 pediatric and adult patients at 27 sites in the U.S. and Australia from December 2021 to March 2025.
Platelets are the blood cells that help stop bleeding by forming clots at cuts or tears in blood vessels. Donated platelets are conventionally stored at room temperature, giving them a shelf life of five to seven days.
Adaptive trial design tested longer platelet storage times in stages
In CHIPS, patients were randomly assigned to receive either standard room-temperature platelets stored for seven days or less, or chilled platelets. Independent data analysts reviewed outcomes after every 200 patients treated. Each time the chilled platelets performed as well as room-temperature platelets, researchers added up to five more days to the storage window and enrolled another 200 patients, continuing until they reached 21 days.
Platelets refrigerated for up to 21 days controlled bleeding as effectively as room-temperature platelets stored for up to seven days, the researchers found. Because blood banks can take two days to process donations, the finding could extend platelets' usable life for controlling bleeding by nearly four-fold.
Chilled platelets could cut platelet transfusion waste that costs hospitals millions
Of the 2.5 million room-temperature platelet units collected each year in the U.S., 10% to 20% are wasted because of their short shelf life, costing hospitals $300 million, according to a study published in the journal Hematology.
"Our findings could result in major international public health benefits," said lead author Philip Spinella, M.D., professor of surgery and critical care medicine in Pitt's School of Medicine and co-director of Pitt's Trauma and Transfusion Medicine Research Center. "This is incredibly transformative and will dramatically improve the availability of platelets while also reducing waste, allowing hospitals that aren't in major cities to afford to keep this life-saving blood product on hand for bleeding patients."
Rural and community hospitals could gain wider access to platelet transfusions
"Rural and community hospitals, for the most part, simply cannot justify keeping room temperature platelets in stock – they don't see enough severely bleeding patients, so the waste would far exceed the benefit, something our nation's fragile blood supply chain cannot accommodate," said co-author Michael Boisen, M.D., cardiothoracic anesthesiologist and medical director of the UPMC Patient Blood Management Program, who served as principal investigator for UPMC's CHIPS trial site. "So, if we can safely extend the shelf life of platelets and reduce the waste – imagine how many more people we could help."
FDA and other countries are reviewing findings on cold-stored platelet storage limits
The results are under consideration by the U.S. Food and Drug Administration and multiple other countries to revise regulations for use of refrigerated platelets stored for up to 21 days in actively bleeding patients. The findings could also benefit military personnel by making it more feasible to have platelets available in conflict areas, said Spinella, who is also associate medical director of Pitt's Center for Military Medicine Research.
More than 97% of platelets are donated through apheresis, a process in which a donor's blood passes through a machine that collects platelets and returns the rest of the blood to the donor. The average age of platelet donors has increased over the past decade, according to data from Vitalant, which supplied the platelets used in the study and is one of the nation's largest nonprofit blood and biotherapies services providers.
"About 15 percent of hospitals can experience one or more delayed platelet transfusions within any given month due to supply shortages," said Ralph Vassallo, M.D., Vitalant's chief medical and scientific officer. "A 21-day shelf life for cold-stored platelets will reduce outdate rates and ensure platelets are available on hospital shelves when a surge in need occurs."
Trial included children from the start
A unique facet of the trial is that it included children and babies from the start. Usually, clinical trials that aren't specific to pediatric populations will exclude children.
"I believe it is unethical not to include children in a trial when there isn't a rational biological reason to exclude them," Spinella said. "Of the 1,000 participants in our trial, roughly a third were children – which makes sense because it is the very young who bleed the most from cardiac surgery and most frequently benefit from platelets. Our trial will hopefully motivate others to include children in their trials, alongside adults."
Frequently Asked Questions
Q: What did the CHIPS trial find about chilled platelets and platelet transfusions?
A: Researchers found that platelets refrigerated for up to 21 days controlled bleeding as well as standard room-temperature platelets stored for up to seven days in patients having heart surgery.
Q: How long can chilled platelets be stored compared with standard platelets?
A: Chilled, or cold-stored, platelets in the trial were tested with storage up to 21 days, compared with a five- to seven-day shelf life for conventional room-temperature platelets.
Q: Why does extending platelet shelf life matter for rural and community hospitals?
A: A longer shelf life could reduce waste and make it more affordable for rural and community hospitals to keep platelets in stock for patients who are bleeding severely, according to the study's authors.
Additional Resources
- Published study: CHIPS trial results in JAMA
- EurekAlert! release: Trial shows chilled platelets could safely expand lifesaving supply to bleeding patients
- Press contact: Allison Hydzik | UPMC Media Relations
- UPMC Patient Blood Management Program: UPMC Patient Blood Management Program | UPMC | Pittsburgh
- Donate Platelets: Vitalant
- Related UPMC and Pitt coverage: Pitt Launches Trial Tackling the Leading Cause of Death in Kids
- Clinical trial registration: Study Details | NCT04834414 | Chilled Platelet Study "CHIPS" | ClinicalTrials.gov
Multimedia
- Philip Spinella, M.D.
- Michael Boisen, M.D.
- Platelet donation (credit Tim Betler, UPMC)
Social media
- Pittsburgh Trauma and Transfusion Medicine Research Center | LinkedIn
- Center for Military Medicine Research: Posts | LinkedIn
- Pitt School of Medicine (@pittmedicine) • Instagram
- Pitt Health Sciences (@pitthealthsciences) • Instagram
- UPMC (@upmcnews) • Instagram
Authors and Funding
Authors: The complete author list is available in the JAMA article. Funding and Disclosures: This study was funded by the Defense Health Agency Operational Medical Systems through the Defense Health Agency Contracting Activity.
