IHControls consist of the same formalin-fixed microbeads used in IHCalibrators and are delivered in a small vial.
BCS IHControls make Statistical Process Control (SPC) possible for IHC
Figure 1. IHControl vials
- Same formalin-fixed microbeads but this time as a suspension.
- Same measurement traceability to a NIST reference standard.
- Use a pipette or microapplicator to apply 1 microliter of the control onto the slide.
- Ideally, the control is on the exact same slide as the sample.
- Once the microbeads are on the slide, it’s handled exactly as you would for a tissue section.
Before running SPC, you need to select an IHCalibrator level to use as a control for producing daily Levey-Jennings graphs. How to do this is explained in the tutorial on Understanding Metric Calibration.
You should use Metric daily to analyze an image of stained IHControls on the tissue slide and quantify the image relative to the baseline IHControl. The Levey-Jennings graph shows you whether the quantification of the stained IHControl is within acceptable limits from the baseline (Figure 2). You should follow your lab’s guidelines for establishing SPC quality control ranges.
How to Use IHControls
For this representative example, the baseline IHControl stain intensity is illustrated in the first panel. If the IHControl stain intensity matches the Baseline, the readout would be Pass (center panel). If the IHControl stain intensity is visibly lower than the “Baseline” then the readout would be “Fail” (right panel) and may warrant investigation.
Figure 2. How To Use IHControls