Reagents that both clear and dehydrate tissues are known as which of the following?

• A. Universal solvents
• B. Clearing agents
• C. Dehydrants
• D. Infiltration media

Answer: (A)

In tissue processing, the term universal solvents refers to reagents designed to handle more than one step by both removing water and preparing the tissue for embedding. These solvents can act as clearing media while also functioning to dehydrate or assist the removal of residual water, enabling a smoother transition from aqueous tissue to the paraffin of infiltration. The idea is that a universal solvent can fulfill the roles of clearing—making the tissue translucent and compatible with paraffin—and dehydration, by displacing water-containing components, within a single or streamlined step. This contrasts with true dehydrants, which only remove water; clearing agents, which primarily replace the alcohol after dehydration to render the tissue transparent and ready for infiltration; and infiltration media, which are used for embedding (like paraffin) and do not perform the clearing/dehydrating actions. Therefore, the best choice is universal solvents, as they describe reagents capable of both clearing and dehydrating in the processing sequence.