Quality control for cytochemical assays

A method for determining the sensitivity of an assay for the detection of the presence or absence of one, or more, target molecules in a biological sample comprising the steps of:

• a) providing a quality control device, wherein the quality control device comprises a matrix having a front surface and a back surface, wherein the front surface is a reagent surface comprising multiple quality control reagent moieties affixed to the matrix surface, wherein each moiety is spatially located in a discrete section of the reagent surface and each moiety comprises a different concentration of the same target molecule or target molecule mimic, and the back surface of the matrix is an adhesive surface, and wherein the adhesive surface of the matrix is affixed to a removable backing sheet;
• b) removing the backing from the adhesive surface of the matrix and attaching the device to a flat, optically transparent surface;
• c) performing the assay on the quality control device wherein the assay results in the detection of the target molecule;
• and
• d) determining the quality control moiety that contains the lowest concentration of said detectable target molecule or target molecule mimic, wherein determination of the lowest concentration of detectable target molecule or target molecule mimic is indicative of the sensitivity of the assay.

A method for validating the performance of an assay for detecting the presence or absence of a target molecule in a biological sample mounted on a flat, optically transparent surface, comprising the steps of:

• a) providing a quality control device, wherein the quality control device comprises a matrix having a front surface and a back surface, wherein the front surface is a reagent surface comprising at least one quality control reagent moiety affixed to the matrix surface, wherein each moiety comprises a target molecule or target molecule mimic, wherein the back surface of the matrix is an adhesive surface and wherein the adhesive surface of the matrix is affixed to a removable backing sheet;
• b) removing the backing from the adhesive surface of the matrix and attaching the device to the optically transparent surface;
• c) simultaneously performing the assay on the biological sample and the quality control device, wherein the assay results in a detectable signal produced by the target molecule in the sample and the quality control reagent moiety;
• and
• d) detecting the signal, wherein detection of the signal produced by the quality control device is indicative of assay performance validation.

An assay method for the semi-quantitative determination of the concentration of a target molecule in a biological sample mounted on a flat, optically transparent surface, comprising the steps of:

• a) providing a quality control device, wherein the quality control device comprises a matrix having a front surface and a back surface, wherein the front surface is a reagent surface comprising multiple quality control reagent moieties affixed to the matrix surface, wherein each moiety is spatially located in a discrete section of the reagent surface and each moiety comprises a different concentration of the same target molecule, or target molecule mimic, and wherein the back surface of the matrix is an adhesive surface, and wherein the adhesive surface of the matrix is affixed to a removable backing sheet;
• and
• b) removing the backing from the adhesive surface of the matrix and attaching the device to the flat, optically transparent surface;
• c) simultaneously performing the assay on the biological sample and the quality control device, wherein the assay results in a detectable signal generated by the presence of the target molecule in the sample and the quality control moiety;
• and
• d) comparing the detectable signal generated from the target molecule in the biological sample with the detectable signal generated from the target molecule or target molecule mimic in the quality control reagent moiety to semi-quantitatively determine the concentration of target molecule in the tissue sample.