Another Masson's Trichrome control slide uses tissue from which organ?

• A. Kidney
• B. Heart
• C. Skin
• D. Lung

Answer: (A)

Masson's Trichrome staining differentiates connective tissue from muscle and cells by coloring collagen blue, muscle and cytoplasm red, and nuclei dark. For a control slide, you want tissue that clearly shows the blue collagen staining so you can verify the staining worked properly. Kidney tissue is ideal because it has abundant connective tissue in the renal capsule and interstitium around tubules, which stains strongly blue with this method. The strong, distinct blue areas provide a reliable cue that the stain has been applied and differentiated correctly. Other tissues can be more variable or less ideal for demonstrating the blue collagen contrast, so using kidney tissue makes the control slide easy to interpret and diagnose staining quality.