NBF in fixative nomenclature stands for which phrase?

• A. Neutral Buffered Formalin
• B. Normal Buffered Formalin
• C. Neutral Basic Formalin
• D. Non-buffered Formalin

Answer: (A)

Neutral Buffered Formalin is a fixative where formaldehyde is kept in a buffered, near-neutral pH solution. The buffering, usually with phosphate, stabilizes the pH around 7.0–7.4 during fixation. This is crucial because a stable, neutral pH minimizes artifacts and preserves tissue morphology better than unbuffered solutions. In practice, this is the standard 10% formalin solution used in histology, containing formaldehyde in buffered water.

That’s why this option is correct: it names the established fixative standard. The other phrases aren’t correct because they describe nonstandard or contradictory pH states—“normal” isn’t a defining term for fixatives, “non-buffered” lacks pH stabilization and can cause artifacts, and “neutral basic” would imply a basic (alkaline) pH, which does not describe this fixative.