Study backs walking blood banks to save wounded troops

Fresh whole blood transfusion can increase combat casualty survival by up to fivefold compared with standard component blood therapy, according to studies cited in a new medical review by Jennifer M. Gurney, a finding that argues for expanding “walking blood banks,” the military’s system for collecting blood directly from screened soldiers near the point of injury during active combat.

The review traces a century of battlefield transfusion history and cites a 2022 study of more than 1,100 combat casualties, co-authored by Gurney, that found a fivefold increase in survival among patients who received warm fresh whole blood, meaning blood transfused shortly after collection from a living donor, compared with those who received only component therapy, blood separated into red cells, plasma and platelets and transfused as separate products. An earlier 2009 study of more than 350 combat casualties similarly found that fresh whole blood was associated with higher survival than component therapy alone.

A walking blood bank works by prescreening soldiers in a unit for blood type and infectious disease risk before deployment, so that when a casualty needs blood urgently, screened donors nearby can be called on to give blood that is transfused within minutes to hours, rather than relying solely on stored blood products shipped from the rear. The review describes this as a “layered approach,” in which fresh whole blood from walking blood banks supplements, rather than replaces, standard blood products already supplied through the military’s blood program.

Hemorrhage remains the leading cause of death from survivable injuries in both military and civilian trauma care, according to the review. A separate 2017 study published in the Journal of the American Medical Association found that combat casualties transfused within 36 minutes of injury had significantly higher survival rates than those transfused later, reinforcing the case for blood delivered as close to the point of injury as possible.

The review traces how this lesson has been learned and lost repeatedly across a century of American wars. By the end of World War I, whole blood transfusion was practiced widely at American military hospitals, with more than 10,000 transfusions performed in 1918 alone. That capability was not carried into World War II, when the U.S. entered the conflict without an established blood banking system. Early in the war, mobile “bleeding teams” collected fresh whole blood from donors near the front, and by March 1945 the U.S. was shipping up to 62,000 units of whole blood per month to the European and Pacific theaters.

The pattern repeated after the war. The Korean War began without an operational military blood program, and the first blood shipments did not arrive until more than two months into the conflict, a delay the review links to preventable deaths among U.S. servicemembers. Whole blood use continued through the Vietnam War, with roughly 600,000 units transfused to more than 330,000 American and allied casualties between 1965 and 1971, before the military shifted toward component therapy in the war’s later years, a change the review attributes to logistics and cost rather than clinical evidence.

The wars in Iraq and Afghanistan prompted the most recent reassessment. The military reintroduced warm fresh whole blood through walking blood banks in 2002, and in 2017 reintroduced low-titer group O whole blood, a universal blood type that can be given to any patient regardless of their own blood type. Low-titer group O whole blood had been recognized as lifesaving as early as World War I but disappeared from military use after Vietnam and was not reintroduced into the U.S. military system until 2016.

Fresh whole blood remains restricted to military use and is not approved by the U.S. Food and Drug Administration for routine civilian care, primarily because it cannot undergo the same infectious disease screening required for standard banked blood before transfusion. The review calls for walking blood bank capability to become a standing practice within military units rather than a last resort, arguing that the survival benefit demonstrated in combat casualty data justifies training and rehearsing the capability before it is needed, not after.

Ukraine has provided a live case study of these principles under active combat conditions. A May 2026 study published in Critical Care, drawing on clinical experience at Ukrainian Role 1 and Role 2 battlefield facilities, found that Ukrainian medical teams have at times administered low-titer group O whole blood without full verification of antibody titers under combat pressure, identifying roughly 30 cases between 2024 and 2026 of mixed-field agglutination, a complication linked to massive transfusion of unverified “universal” donor blood. Gurney was a co-author of a separate 2024 paper cited in that Ukrainian study, arguing that type-specific whole blood still has a role in severe trauma care even as low-titer group O blood has become the dominant battlefield product. Separately, U.S. military medical instructors have trained Ukrainian healthcare workers in emergency fresh whole blood transfusion techniques since early in the war, adapting curricula used by U.S. special operations units for Ukrainian frontline conditions, according to a 2024 paper published in Military Medicine.

The review notes that direct clinical comparisons between fresh whole blood and low-titer group O whole blood remain absent from the published academic literature, and calls for further trials to determine which product benefits which patients under which battlefield conditions.

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