University of Rochester Medical Center researchers found an association between large-scale transfusions using non-identical ABO blood components and higher mortality among trauma patients.
The analysis of 403 patients treated under massive transfusion protocols from 2008 through 2020 found mortality was about twice as high among patients who received six to 15 transfusions when mismatched blood components were used.
The findings were reported in a research letter published this month in JAMA Surgery by Neil Blumberg of URMC's Department of Pathology and Laboratory Medicine and colleagues in the Department of Surgery.
Why emergency transfusions can involve mismatches
Trauma patients and others who need large volumes of blood may receive Group O blood before clinicians know their blood type. Group O red blood cells are widely used in emergencies, but blood components can contain antibodies that do not match the recipient's ABO type.
Doctors and researchers have generally considered that practice safe when immediate treatment is needed, according to URMC. The new analysis compared outcomes for patients who received non-identical blood components with those who received similar quantities of ABO-identical blood.
Blumberg said the result challenges a longstanding assumption that lacked supporting data. The study reports an association, however, and the source does not say the analysis proves the mismatched components caused the higher mortality.
Researchers call for safer universal blood
Blumberg stressed that transfusions are often necessary and lifesaving in trauma care and that the need to treat a patient can outweigh concerns about non-matching antigens.
The researchers said the findings strengthen the case for developing a more universal donor product: Group O blood with A and B antibodies reduced or removed. Current methods for producing such blood are not widely available or fully practical, according to the research team.
URMC stopped using ABO-mismatched platelets for hematology and oncology patients about 35 years ago and extended the practice to all transfusion recipients, including surgical patients, in 2005, Blumberg said.
Massive-transfusion and trauma patients remain the last major group to examine, he said. Until a practical alternative is available, the researchers said clinicians should make determining a patient's ABO type a priority and use ABO-identical blood components when possible.
Additional URMC authors were Kelly Henrichs, Debra Masel, Michael Vella, Mark Gestring, Amanda Lippa, Phuong-Lan Nguyen, Akua Asante, Majed Refaai and Christine Cahill, now with Mayo Clinic in Florida.
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