UNIT 11 DECALCIFICATION

Question 1

Most common.
● Fastest decalcifying agent.
● Recommended
concentration: 5-10%
● Rapid in action, exceeding
end-point will impair staining.
● Very corrosive.

Answer 1

nitirc acid

Question 2

Recommended for routine
processing.

Answer 2

nitric acid

Question 3

Causes problems for staining the
cell nuclei due to its acidic
nature

Answer 3

nitric acid

Question 4

Ruins tissue when there’s an over
decalcification that will cause
the nuclei to shrink.

Answer 4

nitric acid

Question 5

Produces good nuclear staining
as long as the procedure is
properly monitored.
● Acid is easily removed by 70%
alcohol

Answer 5

aqueous nitric acid

Question 6

Recommended for urgent
biopsies.

Answer 6

aqueous nitric acid
formol citric acid

Question 7

Good for cortical bone
specimens.

Answer 7

aqueous nitric acid

Question 8

Relatively good nuclear staining.
● Produces less tissue destruction
compared to aqueous nitric acid

Answer 8

formol citric acid

Question 9

Prolonged immersion can cause
tissue distortion
● Recommended for urgent
biopsies.
● Good for cortical bone
specimens.
● Seriously damage tissue
stainability.
● Imparts a yellow color

Answer 9

aqueous nitric acid

Question 10

Might destroy antigens in the
cell. Important in
immunohistochemistry purposes.

Answer 10

aqueous nitric acid

Question 11

Prevented by neutralizing the
tissue with 5% sodium sulfate.
Addition of 0.1% urea solution in
the nitric acid can lessen this
yellow discoloration.
● Irritant. Should be used using a
fume hood.

Answer 11

formol citrate acid

Question 12

A traditional decalcifier that
decalcifies more slowly than
aqueous nitric acid. Quite
rapid in action, exceeding
end-point will impair staining

Answer 12

perenyi fluid

Question 13

Decalcifies and softens tissues at
the same time.

Answer 13

perenyi fluid

Question 14

Nuclear and cytoplasmic staining
is good.
● Maceration is avoided due to the
recommended for urgent
biopsies.
○ More gentle than pure
nitric acid.

Answer 14

perenyi

Question 15

Decalcification is slow for dense
bones therefore it is not recommended for urgent
biopsies.

Answer 15

perenyi fluid

Question 16

Most rapid decalcifier

Poor nuclear staining.
● Tissue distortion if not monitored
properly.
● Imparts yellowish color.

Answer 16

phloroglucin nitric acid

Question 17

Rapid.
● However it produces better
nuclear staining.

Answer 17

hydrocholoric acid

Question 18

Inferior to nitric acid due to its
slower action and greater tissue
distortion.

Answer 18

HCL

Question 19

Hydrochloric acid diluted with
saturated sodium chloride

Answer 19

von ebners solution

Question 20

Permits relatively good cytologic
staining.
● Moderately rapid.
● Does not require washing out
prior to dehydration.

Answer 20

von ebners

Question 21

Recommended for teeth and
small pieces of bone.

Answer 21

von ebner

Question 22

Moderate acting decalcifying
agent

Answer 22

formic acid

Question 23

Can be used both as a fixative
and decalcifying agent.
● It permits excellent nuclear and
cytoplasmic staining.

Answer 23

formic acid

Question 24

Relatively slow in action.
● Requires neutralization of 5%
sodium sulfate and washing out
to remove acid from the tissue.

Answer 24

formic acid

Question 25

Easier to handle compared to nitric and hydrochloric acid.

Answer 25

formic acid

Question 26

Recommended for routine decalcification and postmortem specimens.

Answer 26

formic acid

Question 27

An effective formic acid decalcifier buffered with citrate.

Answer 27

evans and kraijian

Question 28

An effective formic acid decalcifier buffered with formate.

Answer 28

kristensens

Question 29

A formic acid decalcifier with added formalin,claimed to fix and decalcify. ● Acts as both fixative and decalcifying agents together.

Answer 29

gooding and stewart

Question 30

Recommended for autopsy specimens, bone marrow, cartilage and tissues studied for research purposes.

Answer 30

Formic Acid-Sodium Citrate Solution

Question 31

Relatively slow. ● Requires neutralization by 5% sodium sulfate.

Answer 31

Formic Acid-Sodium Citrate Solution

Question 32

Weak decalcifying agent. Not recommended for dense tissues. Recommended for small pieces of bone tissue. ● Not for urgent biopsies.

Answer 32

tricholoroacetic acid

Question 33

Does not produce tissue or cell distortion. Too slow for routine purposes.

Answer 33

citric acid - citrate buffer soln

Question 34

Acts slowly but causes little tissue damage. Conventional stains are largely unaffected.

Answer 34

neutral edta

Question 35

Main disadvantage: Slow decalcifier Slower than acids. Not suitable for urgent work.

Answer 35

chelating agents

Question 36

Preferred decalcifier if the tissue will undergo tests such as immunohistochemistry, enzyme studies or electron microscopy.

Answer 36

neutral edta

Question 37

Very slow decalcifier. ● Causes slight tissue hardening. ● Inactivates alkaline phosphatase activity which can be restored using magnesium chloride.

Answer 37

neutral edta

Question 38

Utilizes exchange resin. ● Hastens decalcification by removing calcium ions from formic acid-containing solutions thereby increasing solubility from the tissue

Answer 38

ion exchange resin

Question 39

Does not require washing out. ● More gentle with the tissues.

Answer 39

trichloroacetic acid