In routine surgical tissue processing, which step follows the absolute alcohol step?

• A. Xylene.
• B. Paraffin.
• C. Water wash.
• D. Formalin.

Answer: (A)

After dehydration with absolute alcohol, the tissue must be cleared with a solvent that is miscible with paraffin to allow infiltration. Xylene serves as the clearing agent because it replaces the alcohol, makes the tissue optically clear, and is compatible with paraffin, enabling paraffin to infiltrate the tissue in the next step. A water wash would reintroduce moisture and undo dehydration, formalin is a fixative used before dehydration, and paraffin comes after clearing and infiltration, not directly after dehydration. So the step following absolute alcohol is clearing with xylene.