Evaluation of erythrocyte washing using the Haemonetics Model 102 Cell Washer

The Haemonetics Model 102 Cell Washer was evaluated for efficiency of leukocyte removal and erythrocyte recovery. Groups of 25 units of blood were washed using five different protocols, including the methods recommended by the manufacturer. Mean erythrocyte recovery ranged from 83% to 91% and median residual leukocytes ranged from 1% to 4% for the five protocols. The mean erythrocyte recovery for units washed with 30 sec of increased pump speed was 95%, while it was 84% for units washed with 90 sec of increased pump speed (P less than 0.001). The median residual leukocytes was 1% for units washed after buffy coat removal and 4% for all other units (P less than 0.001). There was no other significant difference among the different protocols. These findings could not be explained on the basis of age of units, prewash erythrocyte mass, or prewash total leukocytes.