The benefits of WB in resuscitating bleeding patients have been a lesson learned, forgotten, and relearned over the past century.1,3 Type O WB was the primary blood product used in World War I and the early part of World War II (WWII). LTOWB was the primary blood product in the latter parts of WWII, the Korean War, and the early Vietnam War.1,4-6 WB fell out of favor in the decades since, due to the advent of WB manufacturing techniques, where the ability to manufacture WB into components was thought to optimize the use of each donated unit while minimizing the risk of excessive transfusions, thereby reducing the potential for infections and transfusion reactions.7-9 In 1976, Shires and his collaborators introduced another paradigm shift by proposing crystalloids as a bridge to WB for restoring circulating blood volume in trauma resuscitation by resuscitating the interstitial space.10

When the U.S. entered the conflicts in Iraq and Afghanistan, the resuscitation standards were crystalloid and component therapy, starting with red blood cells (RBCs) and adding plasma and platelets in a serial fashion when clinical or laboratory data confirmed coagulopathy was present. With advancing knowledge, this "unbalanced" strategy transitioned toward component ratios designed to closely mimic WB11 and the principles of Damage Control Resuscitation (DCR) were adapted and advocated. This strategy emphasized prompt surgical bleeding control, transfusion of RBCs, plasma, and platelets in a balanced 1:1:1 ratio, prioritization of fresh RBCs, restriction of excessive crystalloid infusion, and measures to prevent acidosis and hypothermia.12-18 In casualties receiving RBCs, plasma, and platelets in a 1:1:1 ratio, a mortality benefit was demonstrated in a large retrospective cohort study examining transfusion practices during Operations Iraqi Freedom and Enduring Freedom.19

Due to observations that warm fresh whole blood had superior clinical results, starting in October 2004, warm fresh whole blood was prioritized to be used on the sickest patients at the 31st Combat Support Hospital at Ibn Sina. While waiting for the blood from the Walking Blood Banks, component therapy was used in a 1:1 ratio of RBC:plasma. 20-22 FWB quickly demonstrated a survival benefit compared to component therapy (CT) both empirically and in observational studies.23,24 The FWB from WBB was almost always Type Specific Fresh Whole Blood but on rare occasions, Group O whole blood was administered to non-group O recipients.24 This FWB survival advantage rekindled interest in the re-utilization of LTOWB provided directly from the ASBP, thereby providing a fully tested, safe and efficacious option for resuscitation.

Starting in April 2016, the ASBP began providing LTOWB that had been fully screened according to FDA standards to forward deployed forces in Iraq and Afghanistan. 25 Simultaneously, the 75th Ranger Regiment's Ranger O Low Titer (ROLO) Whole Blood Program was instituted to augment point of injury WB resuscitation. The program identifies all blood group O members of the unit and then screens them for low anti-A and anti-B antibodies. This form of LTOWB is from a WBB, or WBB-LTOWB which is not FDA approved.26 In April 2018, the Association for Advancement of Blood and Biotherapies (AABB) changed their standards to permit the use of LTOWB for recipients of unknown ABO types who need emergency transfusion, and that the definition of ‘low titer’ would be made by each local transfusion service (the DoD uses a titer cutoff of <1:256).27

Potential benefits of WB include improved hemostatic capacity and decreased overall volume of preservative when compared to an equivalent volume of component therapy1,28 Additionally, civilian data continues to emerge that LTOWB is associated with a significant reduction in mortality.29,302 LTOWB offers the benefit of a quicker time to balanced transfusion compared to using CT because LTOWB offers balanced resuscitation therapy in one bag instead of having to use up to three bags to achieve balanced resuscitation.4 Additionally, the lack of need for a cross match allows LTOWB, a universal donor product, to be used in scenarios where crossmatching is not feasible, such as in the prehospital environment.36

Given the rapid adoption of LTOWB secondary to improved clinical outcomes as well as the logistical feasibility of transporting one product compared to a balanced component therapy resuscitation that requires up to three units, there is a concern that in future operating environments that the supply of LTOWB will be limited. This supply concern, combined with the proven benefits of the long-standing use of Type Specific Whole Blood (TSWB) from WBB, has led the ASBP to decide to bring back TSWB that has been tested and meets FDA standards As a reminder: 1) TSWB from WBB is not an FDA approved product; and 2) prior to the technology to separate whole blood into components, all blood products were either TSWB or LTOWB for emergencies. Given that the U.S. population is 40% Type A, Type A Whole Blood is going to be collected by ASBP for the operational environments. As this practice becomes implemented, Type A Whole Blood will only be used at Role 3 MTFs upon confirmation of the patient’s ABO group. These facilities must have blood banking capabilities that can perform pretransfusion testing specifically ABO blood group determination. This will allow LTOWB to be reserved for prehospital and Role 2 resuscitation and for patients at the Role 3 during the initial phase of resuscitation, when their ABO-group is unknown.31

The ASBP will designate TSWB that is drawn and processed in their facilities as National Blood Bank (NBB) Type Specific Whole Blood (NBB-TSWB). The nomenclature was chosen to be interoperable with other nations that will adopt this practice, given that while the U.S. must comply with FDA standards, other countries use their national standards to indicate the blood has been donated, tested, processed, stored, and shipped in a manner compliant with their regulatory agencies.