[Adaptation of a freezing technic with a low concentration of glycerol for preserving red blood cells resuspended in saline-adenine-glucose].

We describe here a freezing method with a final low concentration of 20% glycerol and storage in a aluminium flask at - 150 degrees C. This technique allows the freezing of red blood cells concentrates collected on CPD and resuspended in SAG, without having to eliminate the SAG solution. For this we used an initial solution of 60% glycerol, which we added to the red blood cell concentrate in two steps separated by a resting time. Accordingly to the final concentration of glycerol, this freezing process is similar to the method currently used in our laboratory. This consists in one step addition V/V of 40% glycerol solution to the CPD red blood cells. The two techniques have been compared after thawing, and washing in a IBM Blood Processor 2991. The following parameters have been studied mainly: --haemoglobin level --residual glycerol --leucocytes and platelets --amount of 2-3 DPG and of intra-erythrocyte ATP. The results of the two freezing techniques are similar. They show that the SAG solution does not impair the intracellular penetration of glycerol. The in vitro qualities of the erythrocytes are well preserved.