In a thoughtfully designed, adaptive clinical trial, University of Pittsburgh School of Medicine physician-scientists demonstrated that the U.S. could triple-to-quadruple the supply of platelets available to help save bleeding patients of all ages and extend the life-saving therapy into rural regions and community hospitals. Platelets are the component of blood that encourage clotting, plugging cuts and tears in blood vessels and stemming blood loss.
Results from the Chilled Platelet Study (CHIPS) trial are announced today in JAMA and under consideration by the U.S. Food & Drug Administration (FDA) and multiple other countries to revise regulations for use of refrigerated platelets stored for up to 21 days in actively bleeding patients.
Of the 2.5 million room-temperature platelet units collected per year in the U.S., roughly 10% to 20% are wasted due to the short shelf life, costing hospitals $300 million dollars, according to recent research 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."
Currently, donated platelets are conventionally stored at room temperature with a 5-to-7-day shelf life. Early studies conducted half a century ago in healthy volunteers led regulators to believe that refrigerating platelets to extend their shelf life made them less effective.
Recent preclinical studies indicated the opposite, though, so Spinella and colleagues designed CHIPS to safely test using refrigerated platelets stored for increasing amounts of time up to 21 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.
The patients were randomized to receive either standard, room-temperature platelets stored for less than seven days or chilled platelets. At every 200 participants treated, independent data analysts looked at the results. If the chilled platelets were performing just as well as room-temperature, they'd add up to another five days to the age of the chilled platelets used and enroll another 200 participants, up to a maximum of 21 days.
The research team discovered that platelets refrigerated for up to three weeks were just as effective at treating bleeding as room temperature platelets stored for up to one week. Since it can take two days for blood banks to process donations, the finding holds the potential to extend the lifespan of platelets for use in controlling bleeding by almost 4-fold.
"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."
More than 97% of platelets are donated through apheresis, where a donor's blood runs from a tube in their arm to a machine that collects the platelets and returns the rest of the blood back to the donor – a time-consuming process. The age of platelet donors has steadily increased over the past decade and younger donors are not replacing the aging donor base fast enough to keep up with demand, according to data from Vitalant , which supplied the platelets for 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."
In addition to the civilian applications, 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 .
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."
Additional authors are listed in the JAMA article.
This study was funded by the Defense Health Agency Operational Medical Systems through the Defense Health Agency Contracting Activity.
