Red cell freezing and its impact on the supply chain.

Red blood cells (RBC) can be frozen in glycerol solutions and stored for many years. Thawed RBC must have the glycerol removed, but the recovered cells have normal survival in humans. Freezing has been used to store RBC of rare phenotypes for more than 40 years. In the 1960s and 1970s, when medical technology and blood use were expanding rapidly and liquid whole blood and RBC storage were limited to 3 weeks, many attempts were made to expand the use of frozen RBC for meeting the needs for a stable blood supply and to have RBC reserves for emergencies. These attempts have largely been abandoned because of the cost of freezing, storing and processing, better management of the larger and longer lived RBC inventory, concerns about the safety of stored RBC that have not received the most up-to-date testing and the losses associated with the short shelf life of thawed RBC. New automated frozen RBC processing systems will potentially allow extending the outdate of thawed RBC to 2 weeks, but will not materially effect the costs or losses associated with the use of frozen RBC. RBC freezing will have little effect on the logistics of blood supply.