The purification of red cells for transfusion by freeze-preservation and washing. V. Red cell recovery and residual leukocytes after freeze-preservation with high concentrations of glycerol and washing in various systems.

Red blood cells freeze-preserved with 40% W/V glycerol in an ionic or low ionic medium at -80 C were washed in one of four commercially available systems: the Haemonetics Blood Processor 15 using a continuous-flow centrifugation procedure, the Fenwal Elutramatic using a continuous-flow centrifugation procedure, the IBM Blood Processor using an automated serial centrifugation procedure, and the Huggins Cytoglomerator using a dilution/agglomeration procedure. Determinations of red blood cell recovery and leukocyte and platelet removal were made for each of these groups. The dilution/agglomeration procedure produced lower red blood cell recovery values and poorer leukocyte and platelet removal than did any of the three wash systems using sodium chloride solutions. The values obtained with the systems using sodium chloride solutions were slightly but significantly different.