Acid fuchsin is used in which staining procedures?

• A. Masson trichrome, van Gieson
• B. Gomori trichrome
• C. Verhoeff
• D. Aldehyde fuchsin

Answer: (A)

Acid fuchsin is the red dye component used in certain trichrome stains to highlight cellular elements like muscle and cytoplasm, providing contrast against connective tissue. In Masson trichrome, acid fuchsin stains muscle fibers and cytoplasm red, while collagen is colored green or blue by another dye, allowing clear separation of fibrous tissue from muscle. In van Gieson, acid fuchsin again marks muscle and cytoplasm red, with collagen taking on a yellow hue from picric acid, making it easy to distinguish connective tissue from muscle. Other options focus on elastic fibers or use different dye systems, so acid fuchsin isn’t part of those protocols.