A method for preparing five-part differential leukocyte analogs from red blood cells includes selecting appropriate red blood cells; treating the red blood cells with a multi-functional reagent system for maintenance of a structural integrity of the membranes of the red blood cells and synchronous adjustment of cell volume, morphology and inclusions; subjecting the treated red blood cells to an intensified fixation; and washing the treated cells for preservation. The present disclosure also relates to leukocyte analogs prepared by the above method, a reagent system used for preparing the analogs, and a quality control and a calibrator including the analogs for use in a hematology analyzer.