In Focus
Whole blood returns
A new era in trauma resuscitation
Hari Krishnan
Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
"Everything old is new again." Few developments in transfusion medicine illustrate this better than the remarkable resurgence of whole blood as Low-Titer Group O Whole Blood (LTOWB).
For more than five decades, trauma resuscitation has relied on component therapy. Today, LTOWB is re-emerging because it better matches the physiology and urgency of haemorrhagic shock. A single unit provides red cells, plasma and platelets, making it easier to issue, faster and simpler to administer.
Trauma – the race against time
Every minute counts when a patient is bleeding to death. Trauma remains one of the leading causes of mortality worldwide, particularly among young adults, and uncontrolled haemorrhage accounts for nearly one-third of trauma-related deaths. During these critical first hours, rapid haemostatic resuscitation can make the difference between life and death.
Whole blood was the standard transfusion product throughout the World Wars, the Korean War and the Vietnam War. The move to component therapy in the 1970s was driven largely by inventory management and product utilisation rather than evidence that it was superior for trauma resuscitation. Modern Damage Control Resuscitation recreates whole blood by transfusing red cells, plasma and platelets in a 1:1:1 ratio. LTOWB provides the same components in a single unit, reducing bedside complexity and time to transfusion.
Why is LTOWB attracting renewed interest?
Military experience in Iraq and Afghanistan demonstrated that fresh whole blood could improve outcomes in patients with catastrophic bleeding. These observations prompted civilian trauma systems to evaluate cold-stored LTOWB, which is now routinely stocked in many Level-I trauma centres.
The evidence supporting LTOWB continues to grow. A recent meta-analysis of more than 58,000 civilian trauma patients reported improved early and overall survival compared with component therapy. Prospective studies have also demonstrated improved short-term survival, reduced blood product use and reassuring safety in both adult and paediatric trauma.
Is LTOWB safe?
The principal safety concern is the passive transfer of donor anti-A and anti-B antibodies when the recipient's blood group is unknown. However, decades of military experience and contemporary civilian studies have demonstrated that clinically significant haemolytic reactions are exceedingly rare when low-titre donor selection protocols are followed. A practical challenge in LTOWB implementation is the lack of a universally accepted definition of "low titer." In North America, most centres use anti-A and/or anti-B IgM titre cut-offs of ≤1:256, although some adopt ≤1:128 or ≤1:64. The UK and Europe similarly use locally validated thresholds, highlighting the need for regional standardisation.
Observational studies have also demonstrated no increase in transfusion-related complications. RhD compatibility remains an important consideration, particularly in females of child-bearing potential, although several trauma systems now permit emergency use of RhD-positive LTOWB when the clinical need outweighs the relatively small risk of alloimmunisation.
Implementing LTOWB: Practical Considerations
Successful LTOWB programmes require careful inventory planning, as activation of Massive Haemorrhage Protocols is unpredictable and varies between trauma centres. Group O donations should undergo ABO confirmation and rapid anti-A/anti-B titre testing before component preparation to identify suitable LTOWB units. In centres with lower trauma volumes, selected units may be retained as whole blood for the first 7–10 days and, if unused, subsequently processed into blood components, minimising wastage. Pre-storage leukoreduction using platelet-sparing filters remains the preferred approach wherever feasible. However, where dedicated LTOWB collection systems are unavailable or unaffordable, using a collection bag with a transfusion port on the mother bag allows direct whole blood transfusion while preserving the option for later component preparation.
Looking ahead
Although evidence supporting LTOWB continues to grow, much of it remains observational. The recently published SWiFT and TOWAR randomised trials confirmed that prehospital LTOWB is safe but did not demonstrate superiority over balanced component therapy, possibly because only one or two units of whole blood were transfused before patients received conventional in-hospital components. The ongoing TROOP trial is expected to provide additional evidence to better define the role of LTOWB in trauma resuscitation.
LTOWB has evolved from a military innovation into an important component of civilian trauma care. For countries with a high burden of trauma, the question is no longer whether whole blood deserves renewed attention—but how best to implement it safely, efficiently and sustainably.
References
1. Morgan KM, Abou Khalil E, Feeney EV, Spinella PC, Lucisano AC, Gaines BA, et al. The efficacy of low-titer group O whole blood compared with component therapy in civilian trauma patients: a meta-analysis. Crit Care Med. 2024. 2. Holcomb JB, Tilley BC, Baraniuk S, Fox EE, Wade CE, Podbielski JM, et al. Transfusion of plasma, platelets, and red blood cells in a 1:1:1 versus a 1:1:2 ratio and mortality in patients with severe trauma: the PROPPR randomized clinical trial. JAMA. 2015. 3. Shea SM, Staudt AM, Thomas KA, Schuerer D, Mielke JE, Folkerts D, et al. The use of low-titer group O whole blood is independently associated with improved survival compared to component therapy in adults with severe traumatic hemorrhage. Transfusion. 2020. 4. Brill JB, Tang B, Hatton GE, Moffatt-Bruce SD, Sperry JL, Brown JB, et al. Is low-titer group O whole blood truly a universal blood product? Transfusion. 2022. 5. Yazer MH, Spinella PC. An international survey on the use of low-titer group O whole blood for civilian adult trauma resuscitation. Transfusion. 2020. 6. Smith JE, Cardigan R, Sanderson E, Silsby L, Rourke C, Barnard EBG, et al. Prehospital whole blood in traumatic hemorrhage: a randomized controlled trial. N Engl J Med. 2026. 7. Sperry JL, Guyette FX, Cotton BA, Luther JF, Utarnachitt RB, Kutcher ME, et al. Prehospital resuscitation with type O whole blood for trauma and hemorrhage. N Engl J Med. 2026.
