The invention relates to the field of flow cytometry and more particularly to a panel of antibody reagents conjugated to fluorescent compounds. Provided are reagent compositions, comprising at least eight distinct fluorochrome-conjugated antibodies comprising a set of at least there identification antibodies for the identification of a leukocyte population of interest and at least four characterization antibodies for further characterization and/or classification of said leukocyte population. Also provided are kits and methods related to the reagent compositions.