Santa Barbara Cottage Hospital Santa Barbara, California, United States
Background/Case Studies: The use of blood warmers during transfusions for patients with cold autoantibodies has been debated, with varying opinions on their utility. Cold autoantibodies are typically IgM antibodies reacting below physiological temperature and are mostly clinically insignificant. However, IgM cold autoantibodies with a broad thermal amplitude can cause agglutination or hemolysis, prompting blood warmer use. This study describes a revised blood bank workflow aimed at optimizing cold autoantibody identification and management, thereby reducing unnecessary blood warmer usage.
Study
Design/Methods: Historically, blood warmers were utilized for all patients with cold autoantibodies in our organization, regardless of reactivity phase. In early 2025, a workflow revision was implemented to improve the accuracy of cold autoantibody identification and to assess the clinical necessity for blood warmer use. Instead of performing routine cold screening early in the work up, tube screening is performed to obtain reactivities at each phase (at Immediate spin, 37°C, and at Anti-human Globulin) to determine the clinical significance of reactivity and the necessity for blood warming. This allows for a determination of the clinical significance of the reactivity and the need for blood warming, ensuring that warmers are used only when clinically indicated.
Results/Findings: Table 1 shows the number of antibody identification workups performed and the number of patients blood warmers were recommended to:
In 2023, 635 antibody identification workups revealed 127 cold autoantibodies, resulting in 127 blood warmer recommendations. In 2024, 495 workups identified 138 cold autoantibodies, resulting in 138 blood warmer recommendations. Following the workflow changes in 2025, 179 antibody identification workups identified only 10 of these workups recommending blood warmers. This represents a substantial decrease in both the number of cold autoantibodies requiring warming and the number of blood warmers used, from approximately 27% of cases requiring warming in 2024 to approximately 5% in the first five months after implementation of the new workflow. Even though the revised methodology was implemented only in early 2025, a notable reduction in unnecessary use of blood warmers has already been observed.
Conclusions: The revised workflow significantly reduced unnecessary blood warmer usage in patients with cold autoantibodies, improving resource allocation and efficiency. This optimized workflow reduces healthcare costs associated with unnecessary equipment utilization and potentially enhances patient outcomes by avoiding unnecessary interventions. The utilization rate of blood warmers now better reflects clinical necessity, potentially improving patient outcomes and resource management.
