Which solvents can be used for dehydration in histology processing?

• A. Dioxane, methanol, and ethanol
• B. Water, saline
• C. Acetone only
• D. Xylene only

Answer: (A)

Dehydration in histology means removing water from tissue so it can be infiltrated with paraffin. This requires solvents that mix with water and with the embedding medium, allowing water to be gradually replaced. Ethanol and methanol are classic dehydrants because they are fully miscible with water and also compatible with subsequent paraffin infiltration. Dioxane can serve as an alternative dehydrant and often acts as a transitional solvent between alcohols and paraffin, aiding efficient dehydration and infiltration in some protocols. Water or saline cannot perform dehydration since they add water to the tissue rather than remove it. While acetone can act as a dehydrant in some methods, it’s not the standard choice used alone in routine processing, and xylene is typically a clearing solvent after dehydration, not a dehydrant. So, the solvents that can be used for dehydration include dioxane, methanol, and ethanol.