Studies of the Metabolic Integrity of Human Red Blood Cells after Cryopreservation

Human red blood cells subjected both to the sub‐zero temperatures and processing of a low‐glycerol‐rapid‐freeze method for cryopreservation and to subsequent storage at 4 C, under a variety of conditions, consistently maintained concentrations of ATP comparable to those of their nonfrozen, nonprocess d counterparts. Their potassium content was similarly unaffected. The cell sodium was increased by about 10 per cent as a result of the cryopreservation procedure, and during a subsequent storage period at 4 C it increased to a final concentration of from 10 to 13 per cent greater than that of the nontreated red blood cells. Cryopreserved red blood cells were capable of reinitiating sodium and potassium transport activities with a facility equal to that of nonfrozen cells which indicates that the cryoprocessing is protective of enzyme systems essential for this mechanism.