Demand for human leukocyte antigen or human platelet antigen‐selected platelets: An observational study at Canadian Blood Services

Background Platelet transfusion refractoriness (PTR) is a clinically important condition. The Human Leukocyte Antigen and Human Platelet Antigen (HLA/HPA) Platelet Program at Canadian Blood Services (CBS) provides platelet products to support such patients. This study provides a blood operator perspective on the provision of products for the management of immune‐mediated PTR (iPTR), including the evaluation of patient data to determine trends in the prevalence and diagnoses associated with iPTR. Study design and methods A retrospective observational study of patients enrolled in the CBS HLA/HPA Platelet Program between April 2021 and March 2025. Patient demographics and platelet product issuance were extracted from internal electronic records. Descriptive statistics were utilized for baseline characteristics and linear regression for temporal trends. Results We identified 788 cases representing 688 unique patients. Median patient age was 60.5 years. The most frequent diagnoses were acute leukemia (44%) and myelodysplastic syndrome (15%). HLA/HPA platelet issuance showed a statistically significant upward trend (average increase 23 units/quarter, p = .004). Platelet requests strongly predicted units issued ( R 2 = 0.92, p < .001), whereas the number of cases was a weak predictor for the number of platelets issued. Discussion The CBS HLA/HPA Platelet Program has experienced a rise in product demand. The strong relationship between product requests and issuance demonstrates the responsiveness of this program, though variability in fill rates and the limited predictive value of case counts highlight ongoing operational challenges. These findings can inform strategies for donor recruitment, inventory management, and case management to ensure reliable access to compatible platelets for sensitized patients.