The first two years of the use of low titer group O whole blood during French Military overseas operations: A retrospective study.

BACKGROUND: On the battlefield, hemorrhage is the main cause of potentially preventable death. To reduce mortality due to hemorrhagic injuries, the French Military Medical Service (FMMS) has deployed low titer group O whole blood (LTOWB) since June 2021 during operation BARKHANE in the Sahel-Saharan strip. Questions persist regarding the circumstances under which the FMMS employs LTOWB during overseas operations. STUDY DESIGN: We performed a retrospective analysis of all LTOWB transfused by the FMMS during overseas operations in the Sahel-Saharan strip between June 1, 2021, and June 1, 2023. Information was collected from battlefield forward transfusion sheets. RESULTS: Over the 2-year study period, 40 units of LTOWB were transfused into 25 patients. Of the 25 patients, 18 were combat casualties and seven were transfused for non-trauma surgery. Of the 40 units of LTOWB transfused, 22 were provided during Role 2 care, 11 during tactical medical evacuation (MEDEVAC), and seven in light and mobile surgical units. Among combat casualties, LTOWB was the first blood product transfused in 13 patients. In combat casualties, 6 h post-trauma, the median ratio of plasma: red blood cells (RBCs) was 1.5, and the median equivalent platelet concentrate (PC) transfused was 0.17. No immediate adverse events related to LTOWB transfusion were reported. CONCLUSION: LTOWB is transfused by the FMMS during overseas operations from the tactical MEDEVAC until Role 2 care. Deployment of LTOWB by the FMMS enables an early high-ratio plasma/RBC transfusion and an early platelet transfusion for combat casualties.

Multicenter evaluation of a high-throughput microarray platform for extensive red blood cell phenotyping and antibody screening.

BACKGROUND: Blood typing and antibody screening are key elements of transfusion safety. However, available single platform, flexible, and affordable technologies are limited, especially for extended phenotyping. Microarray-based technology allows for this extended phenotyping with the flexibility of piecemeal analysis. STUDY DESIGN AND METHODS: This study was conducted in three blood donor laboratories to determine the performance of a high-throughput microarray-based system for ABO, RH1-RH5, and KEL1 typing, ABS and extended phenotyping (RH8, KEL2&3, FY1&2, JK1, MNS3). Specimens were tested simultaneously on local platforms and on the microarray-based system. When discrepancies were identified, resolver testing were performed. RESULTS: In total, 4862 blood samples were tested for standard phenotype, 4257 for antibody screening and 2194 for extended phenotype. Results were available for 92.12% of the samples. The overall percent agreements were: 100% for ABO, 99.8% for RH1, 99.24% for RH2-5 and 99.86% for KEL1, 93.16% for antibody screening, and 99.68% for extended phenotype. CONCLUSIONS: This microarray-based system provides highly comparable results to current CE marked assays. The ability to continuously test 3000 microarrays in 1 day, providing simultaneously both extended RBC phenotyping and antibody detection drives laboratory efficiencies. The results of our study validate the performance of this new technology; however, the percentage of samples without results must be reduced and further analysis is required to interpret the ABS screening performances. This could constitute a real breakthrough in transfusion, making it possible in the long term, on a single platform, to carry out all the analyses necessary for the qualification of donations.

Prevalence of red blood cell alloantibodies among blood donors in the French Military Blood Institute: A 10-year retrospective study.

BACKGROUND AND OBJECTIVES: Screening for red blood cell alloantibodies (RBC-Ab) is a critical step in ensuring blood transfusion safety performed by blood donation screening laboratories. We aim to evaluate the prevalence of the RBC-Ab among healthy blood donors. MATERIALS AND METHODS: Antibody screening of serum of all voluntary blood donors was performed as a routine immune-haematological procedure by a solid-phase method on a fully automated immunohaematology analyser. Positive sera were further investigated to identify the specificity of RBC-Ab by a commercially available red cell panel. RESULTS: Between January 2012 and December 2021, a total of 212,218 donations were screened for the presence of RBC-Ab, 74% from male donors (n = 157,898) and 26% from female donors (n = 54,320). Mean age at donation time was 32 ± 12 years. A total of 1007 donations were screened positive (0.47%), and 131 were confirmed positive for alloantibodies in their serum, yielding a prevalence of 0.06% (95% confidence interval: 0.05-0.07). Most frequent alloantibodies identified were of RH blood group system (64%), followed by anti-MNS (19%), anti-Kidd and Lewis (6% each) and anti-KEL (4%). The results showed a statistically higher prevalence of alloantibodies in women than men. Our results showed a lower prevalence as compared to the available data, which might be related to our study population. CONCLUSION: The prevalence of positive antibody screening in healthy donors in this study was found to be 0.47%, while the prevalence of alloantibodies was 0.06%. The most common alloantibodies were anti-RH1 (25%) and anti-RH3 (24%).

Implementation of Low Titer Whole Blood for French overseas operations: O positive or negative products in massive hemorrhage?

Massive hemorrhage is the leading preventable cause of death during military operations. During these operations, the delay between initial treatment and arrival at a surgical facility is considerably longer than in Metropolitan settings. This increased prehospital period requires the availability of blood products during the prehospital stage and justifies the availability of Low Titer Whole Blood (LTOWB) for surgical facilities. This product is a fully authorized labile blood product processed by the French Military Blood Institute according to French regulations. Its shelf life is 21 days when stored between 2 and 6°C. It provides the three products necessary for the transfusion management of war injuries in a single product and in physiological proportions. The low anti-A and anti-B titers (<1/64) make LTOWB compatible with any recipient. However, the RhD antigen remains an issue due to its potential harm in cases of transfusion to a D-negative childbearing-age woman due to the potential risk of fetal-maternal incompatibility. This risk must be balanced with the availability of D-negative blood products. Considering the epidemiology of war injuries and LTOWB use guidelines, in addition to the current knowledge on anti-RhD fetal-maternal alloimmunization, the harm-benefit assessment favors the use of RhD-positive LTOWB during overseas operations. Follow-up of childbearing recipients and setup of countermeasures to prevent alloimmunization in those cases remain key points of transfusion safety.