ASCP Tissue Processing 3

Question 1

Which reagent is used for decalcification of bone specimens?

Accepted Answer

EDTA or nitric acid

Answer

EDTA (chelating agent) and nitric acid are common decalcifying agents that remove calcium from bone to allow sectioning.

Question 2

What is the consequence of over-decalcification on tissue?

Accepted Answer

Loss of nuclear staining and tissue damage

Answer

Over-decalcification damages nucleic acids and proteins, resulting in poor nuclear staining and compromised tissue morphology.

Question 3

A tissue block shows a grainy, washed-out appearance after H&E staining. What processing artifact is most likely responsible?

Accepted Answer

Under-fixation

Answer

Under-fixation allows continued autolysis, resulting in poorly preserved, washed-out tissue morphology after staining.

Question 4

What is the purpose of the post-fixation step using osmium tetroxide in electron microscopy preparation?

Accepted Answer

Fixation of lipids and enhancement of contrast

Answer

Osmium tetroxide fixes lipids and adds electron density to membranes, enhancing ultrastructural contrast for electron microscopy.

Question 5

Which endpoint test is used to determine if decalcification is complete?

Accepted Answer

X-ray examination or chemical endpoint test

Answer

X-ray examination verifies calcium removal radiographically, while the chemical test detects calcium ions in the decalcifying solution.

ASCP - Histotechnician Test Practice Test