Cryopreservation of red blood cells.

Cryopreservation of red blood cell concentrates (RBCs) is an important method for maintaining an inventory of rare RBC units and managing special transfusion circumstances. The permeating additive glycerol is used as a cryoprotectant to protect RBCs against freezing damage. The use of thawed RBCs was hampered a 24-h outdating period due to potential bacterial contamination when a functionally open system was used for addition and removal of the glycerol. With the introduction of a functionally closed system for the glycerolization and deglycerolization of RBC units, extended post-thaw storage became possible. Here, we describe the cryopreservation of red blood cells according to the high-glycerol method, using a functionally closed processing system.