Which statement about paraffin adherence to slides is true?

• A. Paraffin sections will not adhere well to clean, untreated, and uncharged slides.
• B. Paraffin sections will adhere well to clean, untreated, and uncharged slides.
• C. Paraffin sections require magnetic slides.
• D. Paraffin sections adhere to all slides equally.

Answer: (A)

Paraffin-embedded tissue needs a slide surface that can hold the waxy section in place through all the processing steps. Paraffin is hydrophobic and does not form strong bonds with a bare, untreated glass surface. That means, on clean, untreated, uncharged slides, the paraffin sections tend to lift or detach during de-waxing, rehydration, or staining. To ensure reliable adhesion, slides used for paraffin sections are typically treated or coated to provide a positive charge or adhesive properties (such as poly-L-lysine, silanized coatings, or commercially adhesion-promoting slides). That’s why the statement that paraffin sections will not adhere well to clean, untreated, uncharged slides is the correct one: without a treated surface, adhesion is poor. The other ideas—that they adhere well to untreated slides, that magnetic slides are required, or that adhesion is equal on all slides—don’t fit with how slide surfaces influence tissue sticking through the protocol.