How IHControls™ Compare To Tissue Sections As Controls
The IHControls™ are intended as on-slide controls to verify correct performance of the stain on each and every slide. Since the IHControls™ are not comprised of tissue or cells, there is no possibility that it could be confused with the actual patient sample.
Reproducibility – IHControls™ are the same day to day over the course of the year. Patient tumors are, by definition, variable and non-standardized.
Ease of use – After finding a suitable tissue control from the paraffin block archive, it must be microtome-sectioned and mounted. Typically, a period of time must pass (years) before a patient tumor sample can be considered a “discard”, for use as a staining control. Applying a 1-microliter droplet of IHControls™ is accomplished in a relatively easy and straightforward manner.
Antigen retrieval – Formalin-fixed paraffin-embedded tissue controls generally require antigen retrieval, testing an important aspect of the total IHC stain process. The same is true for IHControls™, which also generally require antigen retrieval for optimal IHC staining.
Quantitation – Tissue controls are heterogeneous. IHControls™, on the other hand, were specifically designed for standardized quantitative measurement, facilitating inter-laboratory comparison of staining intensity. IHControls™ include internal negative and positive color standard microbeads to compensate for differences in microscopy.
Internal specificity checks – Tissue controls have a built-in set of specificity checks, comprising other antigenically irrelevant proteins. IHControls™ also have internal specificity checks, comprising at least one other microbead type coupled with an irrelevant antigen.
Role in pre-analytic verification – Leftover paraffin-embedded tissues that were fixed, processed, and embedded at some date in the past do not serve as a control for those processes on future days. The same is true for IHControls™. Neither serve as controls for pre-analytic variables.
Counterstain control – Tissue controls will take up a counterstain. IHControls™ will not, and therefore are not appropriate as a control for a counterstain.