Precision transfusion medicine in the omics era.

Transfusion medicine has practiced a form of precision medicine for decades through compatibility testing, infectious disease screening, component manufacturing, traceability, and hemovigilance. Yet blood is still often treated primarily as a commodity-collected, processed, stored, and transfused-rather than as a dynamic biological product rich in molecular information. This Perspective argues that the field is uniquely positioned to extend its long-standing precision framework into a more molecular, longitudinal, and predictive era. Omics approaches, especially genomics and repeated metabolomic or proteomic profiling, can help define stable donor traits, track physiologic changes across the donation career, and connect donor biology to storage quality, posttransfusion performance, and recipient outcomes. Clinical metabolomics may eventually extend this framework to recipients, enabling deeper phenotyping across the full vein-to-vein continuum. This vision supports the emergence of the "blood unit+," a blood product enriched not only by compatibility and availability but also by biological context that may inform quality, resilience, and transfusion efficacy. At population scale, longitudinal donor testing could transform blood systems into distributed observatories of public health or health weather stations, enabling molecular epidemiology, digital donor twins, and more meaningful reciprocity with donors. Integrated with artificial intelligence, these data could help strengthen donor recruitment and retention, by engaging a new generation of increasingly health-conscious donors, while supporting the resilience of blood systems facing demographic aging and shifting patterns of donor behavior and linking donor biology, product behavior, and recipient response in ways no other field can presently match.