Abstract: A rapid fluorescence staining method for facilitating flow cytometry analysis of reticulocytes is described. The method comprises contacting cells with a cocktail containing a detergent, sphering agent, and a cell impermeable dye, such as TO-PRO-3, for about one minute. Advantageously, the inventors have found that the cocktail permits the dye to penetrate the cell membrane rapidly.

Abstract: A blood analyzing instrument includes a single transducer for simultaneously measuring the DC volume, RF conductivity, light scattering and fluorescence characteristics of blood cells passing through a cell-interrogation zone. Preferably, the transducer includes an electro-optical flow cell which defines a cell-interrogation zone having a square transverse cross-section measuring approximately 50×50 microns, and having a length, measured in the direction of cell flow, of approximately 65 microns.

Abstract: A method for enumerating and distinguishing between blood cell populations in a biological sample includes the steps of contacting a biological sample with a cell membrane-permeant, red-excited, nucleic acid binding dye, without significantly disrupting the integrity of the cells; exciting this sample with light in one red wavelength; and measuring fluorescence emitted from different cell populations in the sample. This method is particularly desirable for enumerating different WBC subpopulations using flow cytometry. This method is also useful for enumerating reticulocytes or NRBC or mature RBC. This method is enhanced by pretreating the sample with a nucleic acid-specific blocking agent. Dyes useful in this method include, without limitation, SYTO®17 dye, SYTO®159 dye, SYTO®60 dye, SYTO®61 dye, SYTO®62 dye, SYTO®63 dye, and SYTO®64 dye.