Background: Whole blood (WB) is an attractive product for prehospital treatment of hemorrhagic shock and for initial in-hospital resuscitation of patients likely to require massive transfusion. Neither our regional blood provider nor our hospital blood bank had recent experience collecting or using WB, so we developed a stepwise process to gather experience with WB in clinical practice. Methods: When our Transfusion Committee suggested a WB program, we worked with our regional blood provider to collect cold-stored, leukoreduced, low-titer anti-A, and anti-B group O RhD positive WB (low-titer group O WB [LTOWB]) and worked with our city Fire Department to integrate it into prehospital care. This work required planning, development of protocols, writing software for blood bank and electronic medical records, changes in paramedic scope of practice, public information, training of clinicians, and close clinical follow-up.Results: Between June 2019 and December 2021, we received 2269 units of LTOWB and transfused 2220 units; 24 (1%) were wasted, two were withdrawn, and 23 were in stock at the end of that time. Most (89%) were transfused to trauma patients. Usage has grown from 48 to 120 units/month, covers all 5 Fire Districts in the county, and represents about 1 /4 of all hospital trauma blood product use. Conclusions: Developing a WB program is complex but can be started slowly, including both pre-hospital and hospital elements, and expanded as resources and training progress. The investments of time, effort, and funding involved can potentially improve care, save blood bank and nursing effort, and reduce patient charges.

McLeod phenotype-caused by the missing Xk protein-is a very rare red cell phenotype, one characteristic of McLeod syndrome, and sometimes associated with X-linked chronic granulomatous disease (CGD). Diagnosis of McLeod phenotype is important for appropriate transfusion management, because red blood cells from all healthy donors will have the Xk protein with its Kx antigen and can lead to red cell antibody formation without the ability to find compatible McLeod phenotype blood for transfusion. We offer a review and approach to diagnosis of the McLeod phenotype and special transfusion considerations.