WASHING ERYTHROCYTES IN A CENTRIFUGAL SYSTEM WITH PARTICULAR REFERENCE TO GLYCEROLIZED CELLS

True countercurrent washing is difficult to achieve with unaggregated erythrocytes because of their small size and tendency to engage in bulk flow. Continuous‐flow centrifugal washing of cells suspended in isotonic saline is extremely efficient, permitting a reduction in the concentration of extracellular contaminant by a factor of 100 in less than five minutes with a wash solution volume less than twice the volume of the cell solution. The introduction of glycerol into a cell suspension decreases sedimentation rates and imposes several obstacles to continuous‐flow wash. The efficiency of centrifugal wash procedures for fully glycerolized cells is poor and a preliminary reduction in glycerol concentration by some other method is necessary before continuous‐flow wash can be used effectively. A preliminary dilution with a hypertonic sodium chloride wash improves sedimentation characteristics, but excessive packing of the crenated cells results in washing hemolysis. Some further dilution with isotonic saline prevents this and permits completion of the wash on a continuous‐flow centrifugal basis. 1968 AABB