The unique makeup of IHControls® is what makes our product quality so far above other off-the-shelf products or homemade controls. Each product includes a positive and negative control as well as an optical reference color intensity standard for objective, reproducible stain intensity quantification.
IHControls are comprised of microbeads of two different sizes:
- IHControls Test Microbeads – The larger (test) microbeads, approximately eight microns in diameter, are coated with portions of protein biomarker peptide epitopes. The IHControls include microbeads for several different commercial tests, combined together in suspension. Typically, 1/3 – 1/2 of the test microbeads are immunoreactive with any single IHC antibody. The remainder will not stain. They serve as a negative (specificity) control.
- IHControls Color Standard Microbeads – There are also smaller (three-micron diameter) microbeads that are permanently colored dark brown, regardless of the IHC staining procedure. The small size of these microbeads readily distinguishes them from the larger microbeads. These smaller microbeads serve as a color intensity standard, for comparison during stain intensity scoring of the test microbeads. Color standard microbeads help standardize color intensity measurements regardless of the optical settings. They will be important in the future, for objective quantitative tracking and comparison of stain intensity.
Unstained (left) and stained (right) IHControls. Each image contains unstained test microbeads (bearing an irrelevant antigen/peptide) and smaller dark brown color intensity microbeads. The image on the right also shows stained test microbeads.
Visual color intensity estimation – the microbead edge typically appears darker than the center because the edge includes a greater area of stained surface that is tangential to the light path. We recommend evaluating microbead color intensity with a 40x objective lens (400x total magnification).