What is the fixative for Gomori Trichrome?

• A. 10% NBF
• B. Bouin
• C. Osmium tetroxide
• D. Zenkers

Answer: (A)

The main idea here is choosing a fixative that preserves tissue structure without introducing color changes or artifacts that would interfere with the differential dyeing in Gomori trichrome. 10% neutral buffered formalin is widely used because it stabilizes proteins and maintains morphology evenly, allowing the dyes to differentiate muscle, collagen, and nuclei cleanly without adding extraneous color.

Bouin’s fixative relies on picric acid and can leave a yellow tint from residual picric acid, which can distort the color balance and reduce contrast in Gomori trichrome. Osmium tetroxide is a heavy lipid fixative used mainly for electron microscopy and would alter staining too drastically for this routine histochemical method. Zenker’s fixative also contains picric acid and mercuric chloride, producing artifacts and color shifts that compromise the stain’s accuracy.

So, using 10% neutral buffered formalin provides reliable, consistent staining for Gomori trichrome by preserving tissue without interfering with the stain’s color reactions.