In Gomori Aldehyde Fuchsin staining, what color are nuclei?

• A. Yellow
• B. Black
• C. Red
• D. Purple

Answer: (A)

In Gomori aldehyde fuchsin staining, the dye combination is chosen to highlight certain connective tissue components, especially elastic fibers and basement membranes, which take on purple to magenta hues. The nuclei, however, do not bind the aldehyde fuchsin strongly, so a counterstain is used to provide contrast. That counterstain often colors nuclei yellow, yielding yellow nuclei against the purple-stained structures. This contrast helps distinguish nuclear material from the surrounding elastic and basement membrane components.