What is the most commonly used decalcifying agent?

• A. Phloroglucin Nitric Acid
• B. Nitric Acid
• C. Von Ebner's (HCl)
• D. Hydrochloric Acid

Answer: (B)

Decalcification is the process of removing calcium from mineralized tissue so it can be cut into thin sections for microscopic examination. Nitric acid is the most commonly used decalcifying agent because it acts quickly to dissolve calcium salts, allowing faster turnaround in routine histology. It is widely available and inexpensive, making it a practical default in many labs. When used with proper timing, it preserves enough cellular detail for routine staining, balancing speed with acceptable tissue preservation. Other acids, like hydrochloric acid or specialized formulations, tend to be harsher and can damage tissue detail, so they’re used less often for routine work. Chelating agents such as EDTA preserve morphology better but work too slowly for rapid processing, which is why nitric acid remains the standard choice.