A method and apparatus that serve as a control and calibrator for assays performed on cells and tissues mounted on a microscope slide is described. The apparatus comprises a quality control moiety, such as a peptide epitope, linked to a particulate object, such as a clear spherical bead and the bead is preferably approximately the size of a cell. The quality control moiety is designed to behave in a similar manner in the assay as an analyte, yielding a positive assay reaction an the bead is retained on a microscope slide during the steps of staining by a novel liquid matrix, which solidifies upon drying and causes adherence of the beads to the microscope slide.
