Simplification of the methods for adding and removing glycerol during freeze-preservation of human red blood cells with the high or low glycerol methods: biochemical modification prior to freezing.

Simple methods have been developed for adding and removing glycerol during freeze-preservation with 20 per cent W/V glycerol at minus 150 C, or with 40 per cent W/V glycerol at minus 80 C. A one-step method with a 35 per cent W/V glycerol solution is used to prepare 20 per cent W/V glycerolized red blood cells, and a two-step method with a 57 per cent W/V glycerol solution is used to prepare 40 per cent W/V glycerolized red blood cells. The systems for washing glycerolized red blood cells have been simplified. This method consists of dilution of the thawed glycerolized red blood cells prior to recovery, followed by on-line dilution of these red blood cells with wash solutions during continuous flow centrifugation. This can be done in any of three commercially available washing systems, and they all use the same sodium chloride solutions. For the 40 per cent W/V glycerolized red blood cells, this process takes about 30 minutes and uses 2.2 to 3.2 liters of the sodium chloride solutions, whereas the 20 per cent W/V glycerolized red blood cells can be processed in about 20 minutes using 1.5 to 2.5 liters. After storage in CPD for three days at 4 C, red blood cells can be freeze-preserved with 40 per cent W/V glycerol at minus 80 C or with 20 per cent W/V glycerol at minus 150 C. When the thawed red blood cells are washed in the Fenwal Elutramatic, the IBM Blood Processor, or the Haemonetics Blood Processor and stored at 4 C in sodium chloride-glucose-phosphate for at least 24 hours before transfusion, they have excellent posttransfusion survival values and normal or slightly decreased oxygen transport function. Alternatively, these red blood cells can be rejuvenated before freeze-preservation so that their 2,3-DPG levels are increased and their affinity for oxygen is reduced. Red blood cells that are stored in CPD at 4 C for as long as 28 days can be rejuvenated with a solution containing pyruvate, inosine, glucose, phosphate, and adenine (PIGPA, Solution A) before freeze-preservation with 40 per cent W/V glycerol at minus 80 C. Any one of the above systems can be used to wash these red blood cells and they can be stored at 4 C in a sodium.