Decalcification Flashcards
Decalcifying agents
1) Acids
2) Chelating agents
3) Ion exchange resins
4) Electrical ionization/electrophoresis
Most common and fastest; for routine purposes; undergo spontaneous yellow discoloration
Nitric acid
Urgent biopsies; needle and small biopsies; large cortical bone
10% aqueous nitric acid
Less tissue destruction than 10% aq NA; for urgent biopsies w/ good nuclear staining; used inside a fume hood
Formol-Nitric acid
Routine purposes; decalcify and soften; maceration is avoided
Perenyi’s fluid
Most rapid decal agent; poor nuclear staining; yellow color formation
Phloroglucin Nitric acid
Inferior to nitric acid; good nuclear staining; for surface decal
HCl/muriatic acid
For teeth and small pieces of bone
Von Ebner’s fluid
Moderate-acting; for post-mortem research tissues
Formic acid
For small pieces of bone and teeth; suitable for most routine surgical specimen and immunohistochemical staining
Aqueous formic acid
For autopsy materials, bone marrow, cartilage, and tissues studied for research purposes
Formic acid-Sodium citrate
Does not require washing out; not recommended for urgent exams
Trichloroacetic acid
Weakest decal agent; only for minute pieces of bone
Sulfurous acid
Fixative and decalcifying agent; environmental toxin; highly corrosive; carcinogenic
Chromic acid
Does not produce cell or tissue distortion
Citric acid-Citrate buffer
Combine with calcium ions and other salts to form complexes and facilitate removal of calcium salt
Chelating agents
Most common chelating agent
EDTA
Used as anticoagulant, decal agent, and water softener
EDTA
Commercial names of EDTA
1) Versene (Na2 EDTA)
2) Sequestrene (K3 EDTA)
Hastens decal by removing calcium ions from formic acid, thereby increasing solubility from tissue;
Not recommended for fluids containing mineral acids, such as nitric or hydrochloric acids
Ion-exchange resin
Process where calcium ions (+) are attracted to the cathode (-) and subsequently remived from the decalcifying solution
This process utilizes electricity and depends on direct current to remove calcium deposits
Electrical ionization/Electrophoresis
Solutions used in electrophoresis
1) 88% formic acid
2) conc. HCL
3) DW
A way to measure the extent of decal by touching the tissue or by picking it with a fine needle
Physical/Mechanical method
A way to measure the extent of decal that is very expensive, most, ideal, most sensitive, and most reliable
Not recommended for mercuric-chloride fized tissues
X-ray/Radiologic method
A way to measure the extent of decal that is simple, reliable, convenient; recommended for routine purposes
Decal fluid is replaced every 24-48 hrs
Detect calcium in acid solutions by ppt of insoluble calcium hydroxide/oxalate
Cloudiness = Ca2+ is present (incomplete decal)
Chemical/Calcium Oxalate method
Solutions used in Calcium Oxalate Test
1) conc. ammonium hydroxide
2) saturated aq. ammonium oxalate
Tissue softeners
1) perenyi
2) 4% phenol
3) molliflex
4) 2% hcl
5) 1% hcl in 70% alcohol
