Which statement is true about Tetrahydrofuran in tissue processing?

• A. THF will clear tissue for infiltration.
• B. THF will dehydrate tissue.
• C. THF will stain tissue.
• D. THF is used as a fixative.

Answer: (A)

THF acts as a clearing agent in tissue processing. After dehydration, the tissue needs a solvent that can replace the alcohol and be compatible with paraffin so that the tissue can be infiltrated with embedding medium. Tetrahydrofuran fits this role because it is miscible with both ethanol (and water) and with paraffin, allowing the tissue to become clear and ready for paraffin infiltration. It is not used to dehydrate, stain, or fix tissue. So the true statement is that THF will clear tissue for infiltration.