BACKGROUND O‐negative red blood cells (ON‐RBC) are a precious resource and the international blood banking community has become increasingly concerned with its inappropriate utilization. AABB recently made several recommendations to address the issue. Solutions must be multifaceted and involve donor centers, blood banks, and clinical departments. From the perspective of a hospital blood bank, it is difficult to rely solely on increased donor recruitment and ubiquitous blood typing of the entire in‐patient population. We therefore focused on interventions within the blood bank to optimize inventory and policies to ensure appropriate ON‐RBC utilization. STUDY DESIGN AND METHODS Transfusion data over one year was examined for the rate of out‐of‐group/inappropriate ON‐RBC. Furthermore, we assessed whether that rate was related to product life on the day of transfusion. We also examined our stock inventory levels and how excess inventory can contribute to inappropriate ON‐RBC usage. RESULTS The ON‐RBC inventory level was decreased in order to reduce the rate of inappropriate transfusions while maintaining a safe level for optimal patient care. Compared to baseline, our intervention caused ON‐RBCs to be transfused earlier in their shelf‐life (9.27 vs. 11.15 days from expiration [DFE], p = 0.0012). This reduced the overall rate of inappropriate ON‐RBC transfusions (67% vs. 54%, p = 0.0035), approximating 185 units of ON‐RBC saved over the course of 6 months. CONCLUSIONS A data‐driven approach to optimize stock inventory levels is widely applicable; it can be adopted by numerous institutions to improve utilization and establish a benchmark for the broader blood banking community.

Background: Washing red blood cell (RBC) units prior to transfusion is indicated for certain patients. In the United States, units stored at 1°C-6°C or transported at 1°C-10°C are available for issue up to 24 h, if not used immediately. The washing procedure commonly utilizes room temperature saline resulting in units starting out above the allowed temperature range. This leads to wastage if units are issued and returned too quickly before having a chance to equilibrate in a transport cooler. Study Design and Methods: Here we performed an experimental study of washed RBC quality comparing "ideal" storage conditions in a blood bank refrigerator to a "real-world" simulation of unit transport, including holding in a transport cooler. Twelve RBC units were washed and allocated evenly into either condition.Results: Measurements at 0, 1, 3, 6, 12, and 24 h post-washing revealed that placement in a transport cooler was associated with higher unit temperature prior to 12 h (p = .013) with a maximum difference of 9.3°C. Despite this difference, several measures of unit quality including extracellular potassium, pH, lactate, and free hemoglobin were indistinguishable between conditions (p = .382, .224, .286, .691, respectively). We selected half of the tested units from our irradiated inventory and confirmed increased potassium leak (p < .001) and accumulation of free hemoglobin (p = .012) in irradiated units. Discussion: Washed units stored under approved transport conditions are acceptable to return to inventory up to 24 h after washing and we provide a prediction interval-based temperature threshold for rejecting these units, permitting reduced waste.