Which statement is true about the acids used to decalcify specimens?

• A. Formic acid and nitric acid are used to decalcify specimens.
• B. Formic acid only is used to decalcify specimens.
• C. Nitric acid only is used to decalcify specimens.
• D. No acids are used to decalcify specimens.

Answer: (A)

Decalcification uses acids to dissolve calcium salts in hard tissues so they can be cut into thin, viewable sections. Two acids commonly used for this purpose are formic acid and nitric acid. Formic acid is milder and works more slowly, which helps preserve tissue structure and staining characteristics when you want high-quality morphology. Nitric acid is stronger and decalcifies faster, which is useful when time is a limiting factor, though it can be harsher on delicate details if not carefully controlled. Because both are routinely employed in decalcification protocols—sometimes alone, sometimes in combination—the statement that formic acid and nitric acid are used to decalcify specimens is true. Using only one of them would miss the flexibility of practice, and saying no acids are used would be incorrect since acids are the primary agents that remove calcium in many standard protocols.