Type-specific whole blood still has a role in the era of low-titer O universal donor transfusion for severe trauma hemorrhage.

Whole blood can be ABO-type specific (type-specific whole blood (TSWB)) or low-titer O universal donor (low-titer O whole blood (LTOWB)). Having previously used LTOWB, the US Armed Forces Blood Program began using TSWB in 1965 as a method of increasing the donor pool. In contrast to military practice, the Association for the Advancement of Blood and Biotherapies formerly the American association of blood banks (AABB), from its first guidelines in 1958 until 2018, permitted only TSWB. Attempting to reduce time to transfusion, the US military reintroduced LTOWB in the deployed environment in 2015; this practice was endorsed by the AABB in 2018 and is progressively being implemented by military and civilian providers worldwide. Low-titer O whole blood is the only practical solution prehospital. However, there are several reasons to retain the option of TSWB in hospitals with a laboratory. These include (1) as-yet ill-defined risks of immunological complications from ABO-incompatible plasma (even when this has low titers of anti-A and -B), (2) risks of high volumes of LTOWB including published historical advice (based on clinical experience) not to transfuse type-specific blood for 2 to 3 weeks following a substantial LTOWB transfusion, (3) uncertainty as to the optimal definition of "low titer," and (4) expanding the potential donor pool by allowing type-specific transfusion. Several large randomized controlled trials currently underway are comparing LTOWB with component therapy, but none address the question of LTOWB versus TSWB. There are sufficient data to suggest that the additional risks of transfusing LTOWB to non-group O recipients should be avoided by using TSWB as soon as possible. Combined with the advantage of maintaining an adequate supply of blood products in times of high demand, this suggests that retaining TSWB within the civilian and military blood supply system is desirable. TSWB should be preferred when patient blood group is confirmed in facilities with a hematology laboratory, with LTOWB reserved for patients whose blood group is unknown.