If the power went out 2 hours and 20 minutes after beginning processing, the tissue would be in which station?

• A. Second paraffin
• B. First paraffin
• C. Xylene
• D. Absolute Alcohol

Answer: (A)

The processing sequence moves from dehydration in alcohol through clearing in xylene, then into paraffin infiltration. In many protocols, paraffin infiltration is done in two consecutive steps: a first paraffin step to begin infiltration, followed by a second paraffin step to complete it and fully replace the clearing agent with wax. If 2 hours and 20 minutes have passed since processing began, the tissue would have already progressed past dehydration and clearing and would be in the paraffin infiltration phase. Because the procedure commonly uses two paraffin steps, by that point the tissue is most likely in the second paraffin station, where complete infiltration is achieved. The tissue wouldn’t still be in absolute alcohol or xylene, since those stages occur earlier and are typically completed well before this time frame.