1 INTRODUCTION The practice of cryopreserving red blood cells (RBCs) began in the 1950s, primarily for military applications, preoperative autologous transfusions, and preservation of rare phenotypes.1 While RBC cryopreservation can enable storage for >30 years, adoption of frozen blood programs has been inhibited due to cumbersome and costly processing steps, combined with a limited post-thaw outdate (i.e., 24 h).2 In 2003, the FDA approved the Haemonetics ACP 215 closed-system cell...