What is the temperature of an infiltrating paraffin container?

• A. 37 C
• B. 60 C
• C. 45 C
• D. -20 C

Answer: (B)

Infiltration with paraffin requires the paraffin to be molten so it can penetrate tissue and provide a solid support for sectioning. Most paraffins melt around the mid-50s Celsius, so labs keep the infiltrating paraffin bath at about 60°C to ensure it is fully liquid. At this temperature, paraffin flows well into tissue spaces, giving uniform embedding. Warmer than this risks tissue distortion or antigen damage, while cooler temperatures won’t allow proper infiltration. The other temperatures are either too cool to melt paraffin or far too cold. Hence, around 60°C is used for the infiltrating paraffin container.