Isolation of large numbers of fully viable human reticulocytes using continuous Percoll density gradient

A rapid one-step continuous density gradient centrifugation method for the separation of reticulocytes from peripheral blood is described. Each of 27 blood samples from patients whose initial reticulocytes ranged from 2.1% to 22.8% (X = 7.6%) was subjected to Percoll density gradient separation. Reticulocyte-rich areas were found in the 1.081 to 1.092 density range. The final reticulocyte yield ranged from 73.9% to 98.6% (X = 87.0%) and a recovery of 14.8%. Optimal reticulocyte yields were obtained using centrifugation tubes with an internal diameter of 16 mm and when the tubes were spun for 40 minutes. Two indices that may be reliable indicators of final reticulocyte yield were the mean corpuscular hemoglobin concentration (MCHC). This simple and reliable method can be used to separate platelets, granulocytes, erythrocytes, and mononuclear cells.