Some trauma blood transfusions are questionable, says a new study

New research by a team suggests that a certain type of blood transfusion is not nearly as safe as the medical establishment thinks.

Patients undergoing transfusions in trauma situations or under what are known as massive transfusion protocols often receive group O blood with antibodies that may not match their own, at least as an emergency measure when their blood type is unknown. Doctors and researchers have considered that safe. But in a letter published this month in JAMA Surgery, University of Rochester Medicine Department of Pathology and Laboratory Medicine faculty member Neil Blumberg, MD, and his colleagues from the Department of Surgery reported an association between large-scale nonmatching transfusions and increased mortality.

The research team looked at outcomes for 403 patients who underwent a massive transfusion protocol from 2008 to 2020. Patients receiving mismatched antigens—referred to as an ABO mismatch or an ABO non-identical transfusion*—had higher mortality rates than patients who received similar amounts of ABO-identical blood. Among patients who received 6 to 15 transfusions, mortality rates were approximately twice as high when ABO-mismatched blood was used.

These findings may be controversial because they contradict longstanding dogma, but there was never any data underpinning that dogma.
"And it turns out it was wrong."

The findings are a call to action for work on a solution.

Transfusions are often lifesaving and necessary, and the benefits of going forward in a trauma situation may easily outweigh concerns about nonmatching ABO antigens. However, this new research suggests the need to develop a truly universal donor—group O blood with the A and B antibodies reduced or removed—to improve safety and outcomes. Currently, the ways of doing that are not widely available or entirely practical, but the researchers think their research underscores the need to work on this technology. They also say that it's something doctors should be aware of and, when possible, address by making the determination of a patient's ABO type a priority and administering ABO-identical blood components.

The new findings build on decades of research into the risk of blood transfusions with mismatched antigens.

Neil Blumberg et al, ABO Nonidentical Transfusions and Mortality in Patients Undergoing Massive Transfusion Protocol, JAMA Surgery (2026). DOI: 10.1001/jamasurg.2026.4153

                                                       -------------SSSSSSSSSSSSSSSS-------------

*  ABO mismatch or an ABO non-identical transfusion happens when a patient receives blood products (like red blood cells, platelets, or plasma) from a donor who has a different ABO blood type.