What is the role of tissue control material in IHC assay development?

• A. Help validate consistency across runs and slide sections.
• B. Increase staining intensity artificially.
• C. Replace the need for positive controls.
• D. Has no impact on assay performance.

Answer: (A)

Tissue control material serves as a consistent benchmark to verify that an IHC assay is performing correctly across different runs and across various slide sections. By using tissue with known antigen expression, it lets you detect day-to-day or slide-to-slide variability stemming from pre-analytic factors (like fixation and processing) or analytic factors (such as reagent performance or instrument conditions). This helps confirm that positive staining appears where it should and that background or nonspecific staining stays within expected limits, supporting reliable and reproducible results. It does not artificially boost staining and it does not replace the need for broader positive controls; rather, it provides a practical, real-tie check of overall assay performance.