What is the melting point range of paraffin?

• A. 46-48 deg C
• B. 40-44 deg C
• C. 50-60 deg C
• D. 45-48 deg C

Answer: (D)

Melting point range of paraffin wax used for tissue embedding is the temperature window where solid paraffin becomes fluid, allowing it to infiltrate tissue and form a stable block. Paraffin is a mixture, so it doesn’t melt at a single temperature but over a small range. In routine histology, the wax is formulated so that it remains solid at room temperature but melts readily in a heated bath, typically around the mid-40s to around 50°C. The closest, most representative range is 45-48°C, which aligns with the practical melting behavior of embedding paraffin. The other ranges are either too low to keep blocks stable at room temperature or too high to melt efficiently during processing and sectioning.