DECALCIFICATION Flashcards
Purpose of Decalcification
Purpose:
• Removal of calcium and lime salts
• Done after fixation and before dehydration and impregnation
• Calcium might interfere with accurate evaluation and examination
Significance of Decalcification
• Facilitate normal cutting of tissue in sectioning
• Prevent obscuring microanatomical detail of tissue
Organs that require decalcification:
• Bones
• Tuberculous Lungs
• Arteriosclerotic Vessels
• Teeth
Characteristics of a good decalcifying agent
• Rapid, cheap, inexpensive
• Should also render best and accurate result
• Safe
• Readily available
Unique characteristics of a decalcifying agent
Stable
Easily available
Inexpensive
Easy to prepare
Factors affecting the rate of decalcification
Concentration
Tissue-to-Volume ratio
Temperature
Mechanical agitation
Size and consistency of tissue sample
If agent is less concentrated…
Slow acting
What is the tissue to volume ratio
1 : 20
It is the key to a rapid decalcification of tissue
Mechanical agitation
If the tissue is large and thick…
Longer decalcification process
Four types of decalcifying agents
Acid
Chelating agents
Ion exchange resin
Electrophoreis
Type of acids used in decalcification
Nitric acid
HCl
Formic acid
Trichloroacetic acid
Sulfurous acid
Chromic acid
Citric acid-Citrate buffer sol.
Conc. Of nitric acid
5-10%
Routine of mst commonly used decalcifying agent
Nitric acid
Fastest decalcifying agent in the market now
Nitric acid
Nitric acid imparts a color ______ to the tissue sample through ______ formation
Yellow
Nitrous acid
What is the remedy caused by the yellow coloration of nitric acid
Add urea or sodium thiosulfate/ sulfate
70% ROH
Variations of nitric acid
10% aqueous nitric acid solution
Formol nitric acid
Perenyis fluid
Phloroglucinol-Nitric acid