A simple procedure for the enrichment of reticulocytes by isodense differential centrifugation on silicone oil mixtures.

Utilizing age-dependent differences in the density of red cells, a mixture of silicone oils with density of 1.0806 g/ml was used for the enrichment of rabbit reticulocytes. During concentration, heavy cells, mainly consisting of erythrocytes, move into the silicone oil, whereas the reticulocytes remain above the oil. Suspensions of apparently intact cells with reticulocyte counts of 87 +/- 7.8% and a recovery rate of about 37% were reproducibly obtained. Neither inhibition of cell respiration nor depletion of adenine nucleotides were observed after this enrichment procedure. A micro-modification in hematocrit capillaries seems to be applicable to obtain rapid information about reticulocyte contents in blood samples without staining and counting of cells.