Abstract: A method useful for the enumeration of cell populations in a biological sample includes the steps of reacting in a single reaction mixture a sample, a first antibody labeled with a fluorochrome having a first emission spectrum and an additional antibody. The first antibody binds to an antigenic determinant differentially expressed on leukocytes and non-leukocytes. The additional antibody binds to an antigenic determinant differentially expressed on mature and immature granulocytes or myeloid cells, and is labeled either with the first fluorochrome or an additional fluorochrome having an emission spectrum distinguishable from the first emission spectrum. The reaction mixture can be mixed with a nucleic acid dye having an emission spectrum that overlaps with one of the first or additional emission spectra. The reaction mixture may be treated with a lytic system that differentially lyses non-nucleated red blood cells and conserves leukocytes.

Abstract: A method useful for the enumeration of cell populations in a biological sample includes the steps of reacting in a single reaction mixture a sample, a first antibody labeled with a fluorochrome having a first emission spectrum and an additional antibody. The first antibody binds to an antigenic determinant differentially expressed on leukocytes and non-leukocytes. The additional antibody binds to an antigenic determinant differentially expressed on mature and immature granulocytes or myeloid cells, and is labeled either with the first fluorochrome or an additional fluorochrome having an emission spectrum distinguishable from the first emission spectrum. The reaction mixture can be mixed with a nucleic acid dye having an emission spectrum that overlaps with one of the first or additional emission spectra. The reaction mixture may be treated with a lytic system that differentially lyses non-nucleated red blood cells and conserves leukocytes.

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.