Background Under‐transfusion is an underreported entity within most hospitals and hemovigilance systems. While critical blood shortages are being reported more frequently, without incident codes to document instances of under‐transfusion due to lack of inventory, estimating its impact on patient care as it relates to hemotherapy (HT) has hampered our ability to assess and inform strategic initiatives to combat inventory issues as well as prepare for future blood supply threats. Study Design and Method An 11‐member working group of the AABB (Association for the Advancement of Blood and Biotherapies) Hemovigilance Committee was formed in October 2020 to study the topic of under‐transfusion including its potential causes and clinical expressions. The group was also charged with proposing simple definition/incident codes to be used by hemovigilance systems to document such instances. Results The working group proposed four simple incident codes under the new process code—No Blood (NB)—that can be used by hemovigilance systems to appropriately document instances of under‐transfusion due to lack of inventory. The codes were described as: (1) NB 01—Inventory less than usual level due to supplier shortage; (2) NB 02—Demand for blood product exceeding usual inventory levels; (3) NB 03—Substitution with incompatible/inappropriate units; and (4) NB 04—Suboptimal dose/no transfusion given. Conclusion The adoption of these codes within hemovigilance systems globally would assist in recognition and reporting instances of under‐transfusion due to inventory, thus supporting development of better collection strategies, inventory management techniques as well as effective policies to improve blood safety and availability.

Background Since the beginning of the COVID‐19 pandemic, cryopreservation of hematopoietic progenitor cell (HPC) products has been increasingly used to ensure allogeneic donor graft availability prior to recipient conditioning for transplantation. However, in addition to variables such as graft transport duration and storage conditions, the cryopreservation process itself may adversely affect graft quality. Furthermore, the optimal methods to assess graft quality have not yet been determined. Study Design and Methods A retrospective review was performed on all cryopreserved HPCs processed and thawed at our facility from 2007 to 2020, including both those collected onsite and by the National Marrow Donor Program (NMDP). HPC viability studies were also performed on fresh products, retention vials, and corresponding final thawed products by staining for 7‐AAD (flow cytometry), AO/PI (Cellometer), and trypan blue (manual microscopy). Comparisons were made using the Mann–Whitney test. Results For HPC products collected by apheresis (HPC(A)), pre‐cryopreservation and post‐thaw viabilities, as well as total nucleated cell recoveries were lower for products collected by the NMDP compared to those collected onsite. However, there were no differences seen in CD34+ cell recoveries. Greater variation in viability testing was observed using image‐based assays compared to flow‐based assays, and on cryo‐thawed versus fresh samples. No significant differences were observed between viability measurements obtained on retention vials versus corresponding final thawed product bags. Discussion Our studies suggest extended transport may contribute to lower post‐thaw viabilities, but without affecting CD34+ cell recoveries. To assess HPC viability prior to thaw, testing of retention vials offers predictive utility, particularly when automated analyzers are used.