Decalcification
Pronunciation: dee-kal-si-fi-KAY-shun
A tissue processing step in which calcium mineral is removed from bone or calcified tissue specimens to allow sectioning on a standard microtome.
Full Definition
Decalcification is a preparatory step applied to calcified specimens—such as bone biopsies, teeth, and calcified soft tissue—before routine paraffin embedding. Calcium deposits make tissue too hard to section with standard microtome blades, so they are removed using acid-based agents (e.g., formic acid, hydrochloric acid) or chelating agents (e.g., EDTA). The method and duration must be carefully controlled, as prolonged exposure to strong acids degrades nucleic acids and proteins, compromising downstream IHC and molecular testing. Editors should verify that decalcification method, duration, and endpoint assessment are documented in protocols and reports.
Usage
Usage note: Specify the decalcification method and agent in laboratory reports, as this directly affects what downstream tests are feasible. EDTA is preferred when IHC or molecular tests are planned.
In Context
- "The bone trephine biopsy underwent EDTA decalcification for 72 hours prior to paraffin processing to preserve antigenicity for IHC." — Haematopathology laboratory protocol
- "The pathology report noted that acid decalcification had been used, which precluded reliable FISH analysis on the specimen." — Pathology report — methods section