ASCP Tissue Fixation and Decalcification 3

Question 1

What is the primary purpose of decalcification in histological tissue preparation?

Accepted Answer

To remove calcium mineral deposits so calcified tissue can be sectioned

Answer

To remove lipids so tissue can be infiltrated with paraffin

Answer

To improve the staining intensity of soft tissue components

Answer

To harden soft tissue before microtomy

Question 2

Which decalcifying agent is most commonly used for routine bone processing in histology?

Accepted Answer

Hydrochloric acid (HCl)

Answer

Sulfuric acid

Answer

Acetic acid

Answer

Nitric acid

Question 3

What is the primary advantage of using EDTA for decalcification compared to acid methods?

Accepted Answer

It preserves tissue morphology and antigenicity better, enabling IHC and molecular studies

Answer

It is significantly faster than acid decalcification

Answer

It is more effective for large, dense cortical bone specimens

Answer

It requires no prior fixation step before use

Question 4

Which endpoint test uses a chemical reaction to confirm that decalcification is complete?

Accepted Answer

The ammonium oxalate test, where no white precipitate in the used decal fluid confirms completion

Answer

The bend test, where complete decalcification allows the specimen to flex without cracking

Answer

The radiographic test, where absence of radiodensity on X-ray confirms completion

Answer

The pH test, where a neutral pH of the decal fluid confirms calcium removal

Question 5

When is formic acid decalcification preferred over hydrochloric acid?

Accepted Answer

When nuclear morphology and DNA preservation for molecular studies are important

Answer

When speed of decalcification is the highest priority

Answer

When decalcifying large, dense cortical bone specimens

Answer

When cost reduction is the primary consideration

Question 6

What preparatory step should be performed on tissue BEFORE beginning acid decalcification?

Accepted Answer

Fix in 10% neutral buffered formalin before decalcification

Answer

No prior treatment is needed; decalcification alone is sufficient

Answer

Fix in 70% alcohol for 24 hours before decalcification

Answer

Process through a graded alcohol series before decalcification

Question 7

Which decalcification agent is the fastest but causes the most tissue damage, reserved for cases where speed is critical?

Accepted Answer

Nitric acid (5–10%)

Answer

EDTA chelation

Answer

Formic acid (5–10%)

Answer

Electrolytic decalcification