Which statement about paraffin sections and glass slides is true?

• A. Paraffin sections will adhere well to clean, untreated, and uncharged glass slides.
• B. Paraffin sections will not adhere well to clean, untreated, and uncharged glass slides.
• C. Paraffin sections require metal slides for adhesion.
• D. Paraffin sections adhere best to charged slides only.

Answer: (B)

Paraffin-embedded tissue needs a surface that can grab hold of the section through dehydration and staining. Paraffin is hydrophobic and the bare glass surface is relatively inert, so a section on clean, untreated, uncharged glass tends to detach during processing. To ensure the tissue stays put, slides are given an adhesive treatment or coating (such as poly-L-lysine, gelatin, collagen, or silane/chrome alum treatments) or are made positively charged. This improves protein adsorption and the mechanical grip of the section. Therefore, clean, untreated, uncharged glass slides do not provide reliable adhesion, making that statement true.