Which tissue-to-fixative ratio is typical for preserving tissue for histology?

Which tissue-to-fixative ratio is typical for preserving tissue for histology?

• A. 1 to 1
• B. 1 to 5
• C. 1 to 10
• D. 1 to 50

Answer: (C)

Fixation works best when the fixative can reach every part of the tissue. To achieve that, tissues are kept in a fixative with enough volume to fully immerse the specimen and allow diffusion into the center, rather than just brushing the surface. That’s why small, thin pieces are processed in a generous amount of fixative and the tissue is thoroughly covered to ensure uniform penetration. If the tissue isn’t adequately immersed, the outer parts may fix while the core remains unfixed, leading to poor morphology and unreliable staining. On the other hand, once penetration is achieved and the tissue is sufficiently fixed, adding more fixative doesn’t improve quality and simply wastes material. In practice, the aim is complete immersion and sufficient contact time so fixation is uniform throughout the tissue.

Fixation works best when the fixative can reach every part of the tissue. To achieve that, tissues are kept in a fixative with enough volume to fully immerse the specimen and allow diffusion into the center, rather than just brushing the surface. That’s why small, thin pieces are processed in a generous amount of fixative and the tissue is thoroughly covered to ensure uniform penetration. If the tissue isn’t adequately immersed, the outer parts may fix while the core remains unfixed, leading to poor morphology and unreliable staining. On the other hand, once penetration is achieved and the tissue is sufficiently fixed, adding more fixative doesn’t improve quality and simply wastes material. In practice, the aim is complete immersion and sufficient contact time so fixation is uniform throughout the tissue.