The Patient With Multiple Alloantibodies: A Systematic Strategy for Antibody Identification and Transfusion Management.

Background: For patients with multiple alloantibodies against red blood cells (RBCs), the challenges posed by transfusion practice are immense due to complex serological reactions that make finding matching units difficult. Identifying underlying antibodies is necessary to prevent hemolytic transfusion reactions (HTRs). Objective: To outline a systematized immunohematologic strategy for the detection and management of several alloantibodies in a surgical patient. Methods: A 64-year-old O-positive female was scheduled for spinal surgery and had a positive pre-transfusion antibody screen. Automated and manual techniques, including multi-cell panels, enzyme-treated cells, thermal amplitude testing, extended phenotyping, DAT, and acid elution, were used in antibody investigation. Results: The alloantibodies anti-s and anti-E were proven to be warm-reactive IgG. The cold-reactive IgM alloantibodies anti-P1 and anti-N were similarly shown to exhibit characteristic temperature reactivity. Anti-Fyb was suspected, but not excluded, for a lack of homozygous rule-in cells. Eluates showed an anti-s reaction with transfused RBCs, consistent with recent exposure. Antigen-negative, phenotype-compatible RBCs were selected that only reacted in the antiglobulin stage, although spin incompatibilities were immediate. Conclusion: This case highlights the significance of systematic approaches to antibody rule-in/rule-out, the thermal-phase test, and phenotype-directed transfusion in patients with multiple alloantibodies. A clear distinction must be made between clinically significant IgG antibodies and cold-reactive IgM antibodies to ensure safe, timely transfusion management.