Loyola University Medical Center Woodridge, Illinois, United States
Background/Case Studies: Patients with unknown blood types requiring massive transfusion protocols (MTPs) or emergency release of blood products are given universal blood products consisting of Group O RBCs and Group AB Plasma. However, most individuals will be of Group O or A, which do not require AB Plasma. Multiple trauma centers have started to incorporate utilization of Low Titer Group O Whole Blood (LTOWB). The numerical definition of LTOWB varies among blood donation centers. For the purposes of this study, titer values less than 200 will be used as the cut-off since this coincides with our blood donor vendors, Versiti and the American Red Cross. The goal of this study was to evaluate the use of Group A plasma for MTPs and emergency use. To accomplish this, we assessed anti-B titer levels in Group A patients, plasma, and platelet units. Additionally, MTPs from April 2020-2024 at our institute were assessed to determine the patient blood type demographics and receipt of LTOWB.
Study
Design/Methods: Anti-B titers of 50 Group A patient samples, 50 Group A donor plasma units, and 20 Group A donor platelet units were assessed. Group A patients were screened and selected for those without underlying conditions or medications which could impact antibody production and history of alloantibodies. The anti-B titers, both IgM and IgG, were run in automated gel on the Ortho Vison instrument with 0.8% B Affirmagen reagent red blood cells. Results for each titer were interpreted and documented based on highest dilution with reacting strength of 1+. MTPs were reviewed from April 2020-2024 to determine patient blood type and LTOWB receipt.
Results/Findings: Figure A shows the anti-B titer ranges for patients and products assessed. Patient samples displayed a median anti-B titer of 16 for both IgM and IgG. Of the 50 patients assessed, 1 (5%) displayed an anti-B IgM titer greater than 200 and 2 (10%) with anti-B IgG titer greater than 200. The plasma had median anti-B titer of 8 for both IgM and IgG and all were ≤64. The platelets had median anti-B titers of 2-4 for both IgM and IgG with all ≤32. Out of 448 MTPs, the blood group distribution showed 32.8% Group A, 46.7% Group O, 12.7% Group B, 3.3% Group AB, and 4.5% unknown. There were 89 MTP patients who received LTOWB with 46.1% Group O receiving 1-4 units, 27% Group A receiving 1-4 units, 16.9% Group B receiving 1-2 units, 2.2% Group AB receiving 2 units, and 7.9% unknown receiving 1-3 units. Conclusions: Overall, Group A blood tends to have low levels of anti-B titers. The serologic data shows the anti-B titer levels in Group A plasma and platelets are markedly below the cut-off of 200 used by the donor centers for LTOWB for both IgM and IgG. Therefore, the utilization of Group A plasma and platelets during MTPs and emergency release when the blood type is unknown should be strongly considered.
