Patent ID: 7282350

Claim:
An improved method for detecting and enumerating rare cells in a mixed cell population by obtaining a blood specimen from a test subject, said specimen comprising a mixed cell population suspected of containing said rare cells, which method comprises preparing an immunomagnetic sample wherein said blood specimen is mixed with magnetic particles coupled to a ligand which reacts specifically with a determinant of said rare cells, to the substantial exclusion of other sample components, contacting said immunomagnetic sample with at least one reagent which labels said determinant of said rare cells, and analyzing said labeled rare cells to determine the presence and number of any said rare cells in said inmiunomagnetic sample, wherein the greater the number of said rare cells present in said sample, the greater the severity of a disease state, and wherein the improvement comprises the addition of two or more fluorescently distinct sets of stabilized cell populations, said fluorescently distinct sets having different concentrations with said sets having different intensities, permeabilized, for use as a range of control cells in said method, and wherein the membranes of said control cells are detectably labeled, and wherein said control cells contain stabilized cellular components and antigenic moieties of said control cells stabilized for a period up to six months by exposure to fixative.