Abstract: A method for discriminating and quantifying platelets within an analyzed blood sample involves initially diluting the blood sample with a ghosting reagent that causes a change in the index of refraction of the cell. Owing to the change in the index of refraction, light scattered from the ghosted red blood cells will be substantially reduced relative to light scattered from platelets. This results in locations of platelets within a scatterplot of the analyzed blood sample to fall within a region distinguishable from those containing normal red blood cells, fragmented red blood cells, and microcytic red blood cells.

Abstract: Methods for differentially identifying cells in an instrument employ compositions containing a combination of selected antibodies and fluorescent dyes having different cellular distribution patterns and specificities, as well as antibodies and fluorescent dyes characterized by overlapping emission spectra which form non-compensatable spectral patterns. When utilizing the compositions described herein consisting of fluorescent dyes and fluorochrome labeled antibodies with overlapping spectra that cannot be separated or distinguished based upon optical or electronic compensation means, a new fluorescent footprint is established. This new fluorescent footprint is a result of the overlapping spectra and the combined cellular staining patterns of the dyes and fluorochrome labeled antibodies chosen for the composition. The new fluorescent footprint results in histogram patterns that are useful for the identification of additional cell populations or subtypes in hematological disease.

Abstract: Methods are provided for measurement of nucleated red blood cells in a blood sample. The methods include exposing a blood cell sample to a reagent system to lyse mature red blood cells, subsequently analyzing nucleated red blood cells in a flow cell by axial light loss, DC impedance, and medium angle light scatter measurements; by axial light loss, low angle light scatter, and medium angle light scatter measurements; or by axial light loss, DC impedance, low angle light scatter, and medium angle light scatter measurements; and then differentiating nucleated red blood cells from other cell types by using measured signals and/or functions thereof.

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: Methods are provided for measurement of nucleated red blood cells. The methods include exposing a blood cell sample to a reagent system to lyse mature red blood cells, subsequently analyzing nucleated red blood cells in a flow cell by axial light loss, low angle light scatter and DC impedance measurements, or two selected measurements thereof; and then differentiating nucleated red blood cells from other cell types by using measured signals and/or functions thereof.