University of Washington Medical Center Seattle, Washington, United States
Background/Case Studies: Red blood cell (RBC) units may be washed to reduce plasma-associated complications such as allergic reactions, hyperkalemia, and increased ABO titers. However, washing is time- and resource-intensive, and support for the commonly used cell washer COBE 2991will end in 2030. Our institution instead utilizes RBC supernatant removal via a single centrifugation step and plasma extraction, allowing for an efficient approach to reduce these complications.
Study
Design/Methods: Supernatant removed (SR) RBC units were processed by sterile welding RBC components to a transfer bag, centrifuging at 3164 x g for 5 minutes at 4°C, and expressing supernatant using plasma expressor. We analyzed use of SR RBC units in a cohort of 60 patients transfused from October 2020 to December 2024. Clinical indications were categorized into the following groups: ‘ABO Incompatible Cardiac Transplant’ (patients listed for or receiving ABO-incompatible cardiac transplant), ‘Allergic Reaction’ (prior repeated allergic or moderate allergic reaction to RBC transfusion), ‘T Antigen Activation’ (concern for plasma-associated hemolysis in setting of infection), ‘Hyperkalemia’ (Volume overloaded anuric infant with persistent hyperkalemia), ‘Repeated Reaction’ (one patient with repeated fever and pulmonary transfusion reactions most consistent with transfusion associated circulatory overload). The primary outcome measured was the incidence of allergic transfusion reactions following administration of SR RBC units in patients with history of allergic reactions.
Results/Findings: Of the 60 patients who received SR RBC units, the majority (n=41) were in the ‘ABO Incompatible Cardiac Transplant’ group. Fifteen patients were in the ‘Allergic Reaction’ group (Table 1), and isolated cases were recorded for ‘Repeated Reaction’ (n=1), ‘T Antigen Activation’ (n=2), and ‘Hyperkalemia’ (n=1). The 15 patients in Allergic Reaction group received 420 SR RBC units (mean 28; range 1-146 per patient). One patient with prior allergic transfusion reactions experienced an allergic event (hives and periorbital edema) with an SR RBC unit. After treatment with steroids, diphenhydramine, and famotidine, patient tolerated another SR RBC unit transfusion the same day and 22 subsequent SR RBC transfusions without reaction. No allergic transfusion reactions occurred among the other 14 patients with history of allergic reaction receiving SR RBC units. The incidence of allergic reaction with SR RBC units at our center was ~0.2% compared to reported rates of 1-3% with unmodified units. Conclusions: Single-spin SR RBC units effectively prevented allergic transfusion reactions including in patients with moderate/severe allergic reactions, supporting their use as a viable, efficient alternative to conventional RBC washing—particularly where access to cell washers is limited or rapid turnaround is desired.
