this invention relates to an improved procedure for the multiparameter analysis of leukocyte subpopulations from peripheral blood , bone marrow or any body fluid containing blood nucleated cells , including the quantification of each subpopulation in terms of cells per microliter . the method uses a cocktail of at least four monoclonal antibodies labelled each with a different fluorescent tag , the measurement of at least two light scatter and four fluorescence emissions related parameters and at least one population of fluorescent beads to differentiate and enumerate between and among the different leukocyte subpopulations in the peripheral blood , the bone marrow or other body fluid . it includes : the incubation of the sample with a mixture of monoclonal antibodies conjugated to a minimum of four different fluorochromes , the addition of one or more populations of reference beads , the flow cytometry measurement of the fluorescence emissions associated to each cell and bead population and , the mutidimesional analysis of each cell and bead population present in the sample aimed at its identification , enumeration and characterization .