Test inaccuracies are a major issue for both IHC and FISH.
Pre-analytic, analytic, and post-analytic factors can affect test accuracy. The use of laboratory assays as the sole determinant for therapy selection poses a significant challenge to pathologists performing and interpreting the results and to oncologists who must rely on them for clinical decisions.
IHC and FISH are important testing procedures that dictate a critically effective, yet potentially life-threatening and expensive treatment. Assay standardization is extremely important to reduce the occurrence of inaccurate testing.
This image is of a HER2 IHC stained tissue section. The score for this slide would be 3+. It has complete membrane staining.