The Verhoeff staining method differentiates with which component?

• A. Excess mordant
• B. Rinsing with water
• C. Dark counterstain
• D. Alcohol dehydration

Answer: (A)

In this stain, differentiation relies on the effect of an excess mordant to selectively remove color from non-elastic structures while elastic fibers retain the stain. The iron hematoxylin complex used to mark elastic fibers binds strongly, but when a differentiating solution with excess mordant (ferric chloride in alcohol) is applied, it strips away the stain from components with weaker affinity. This leaves the elastic fibers stained dark (often black), providing clear contrast against other tissue elements that are decolorized or lightly stained. After differentiation, a counterstain (van Gieson) is usually applied to color the surrounding tissue.

Rinsing with water wouldn’t selectively differentiate, a dark counterstain comes after differentiation for contrasting colors, and alcohol dehydration is a processing step that doesn’t differentiate the stain itself.