Which stain uses Kidney as the best control?

• A. Periodic acid-methenamine silver stain
• B. Gomori reticulin
• C. Verhoeff
• D. Aldehyde fuchsin

Answer: (A)

Stains that visualize basement membranes rely on components that are especially prominent in the kidney’s glomerular basement membranes. The periodic acid–methenamine silver stain uses silver to specifically highlight these basement membranes, so kidney tissue provides a reliable, consistent control. The glomerular basement membrane in kidney is thick and rich in glycoproteins, making it easy to confirm that the stain is working properly.

Gomori reticulin targets reticular fibers, with best controls being tissues rich in reticulin such as liver, spleen, or lymph node. Verhoeff and aldehyde fuchsin are used for elastic fibers, with controls like aorta or skin. These contexts aren’t as universally representative for verifying a basement-membrane–targeting stain as kidney is for this stain.