Decalcification Flashcards
Process of removing calcium from tissues following fixation.
Decalcification
What refers to the tuberculous lungs?
Lung tubercle
What is the ratio of fluid to tissue (demineralization)?
20:1
What is the optimal temperature for decalcification?
18-30℃
room temperature
What is the main object of decalcification in a surgical pathology laboratory?
bone
True or False.
Length of the procedure depends on the weight of the tissue.
False. (Length of the procedure depends on the size of the tissue)
What is the tool that is sufficient to routinely and rapidly reduce undecalcified surgical specimens of hard tissue?
Low speed saw
What is the principle of decalcification?
Acids form soluble calcium salts in an ion exchange that moves calcium into the decalcifying solution.
What is the ideal chelating agent that sequesters metallic ions?
14% EDTA
When infiltrated by this, it is possible to polymerize the bone, which causes it to harden and not need to be decalcified anymore.
Acrylic or epoxy resins
What is the part of the bone that does not require softening?
Cartilage
Because of its insoluble keratin filaments, it is a waste of time to put it in a decalcification solution.
Toenails
Identify the decalcifying agent.
i. Most common
ii. Fastest
iii. Minimal distortion
iv. Inhibit nuclear stains
Nitric acid (HNO3)
Identify the decalcifying agent.
i. Inferior to nitric acid
ii. Slower
iii. Distort much greater
iv. for surface tissue blocks
Hydrochloric acid (HCl)
Identify 2 solutions that are both fixative and decalcifyer
Formic and chromic acid
Identify the decalcifying agent.
i. Does not require washing out
ii. Not used for dense tissue
iii. Slow-acting
iv. ONLY suitable for small spicules of bone
v. 4 – 8 days decalcification time
vi. good nuclear staining
Trichloroacetic acid (TCA)
Identify the decalcifying agent.
i. Very weak decalcifying solution
ii. ONLY for minute pieces of the bone
Sulfurous
Identify the decalcifying agent.
i. Permits excellent nuclear and cytoplasmic staining
ii. Doesn’t distort the cell or tissue
iii. Slow for routine purposes
iv. 6 days decalcification time
Citric Acid-Citrate Buffer Solution
How long is the decalcification time when EDTA is used?
6-8 weeks
pH of EDTA
pH 7
Identify the decalcifying agent.
- Can lodge calcium in the bottom area.
- Produce artifacts usually caused by CO2 bubbles
- Hastens decalcification by removing calcium ions from formic acid-containing decalcifying solutions
Ion Exchange Resin
Identify the decalcifying agent.
- attraction of calcium to the negative electrode
- dependent upon a supply of direct current to remove calcium
Electrophoresis
Identify the method for measuring the extent of decalcification.
- Mechanically checked by pricking the tissue with a needle or probe, manipulation, bending probing, or trimming of the specimen.
- Unreliable
Physical or Mechanical Method
Identify the method for measuring the extent of decalcification.
- Simple, reliable, and convenient method for routine purposes.
- Involves detection of calcium in acid solution by precipitation of insoluble hydroxide or calcium oxalate.
Chemical method
