HTL Tissue Processing & Fixation 3

Question 1

Which tissue processing schedule is most appropriate for a large, fatty breast specimen to ensure adequate fixation?

Accepted Answer

Extended processing with additional formalin fixation steps

Answer

Large fatty specimens require extended processing with additional fixation and dehydration steps because fat impedes reagent penetration, requiring longer infiltration times.

Question 2

What is the primary advantage of using a vacuum during paraffin infiltration on automated processors?

Accepted Answer

It removes residual clearing agent and air bubbles, improving wax penetration

Answer

Vacuum application during paraffin infiltration removes trapped air and residual clearing agents from tissue cavities, allowing complete and uniform paraffin penetration.

Question 3

Glutaraldehyde is the preferred fixative for electron microscopy because:

Accepted Answer

It provides superior ultrastructural preservation via extensive protein cross-linking

Answer

Glutaraldehyde has two aldehyde groups that create more extensive protein cross-linking than formalin, providing superior preservation of ultrastructural detail required for TEM.

Question 4

When processing bone specimens for histology, decalcification is performed:

Accepted Answer

After fixation and before dehydration

Answer

Bone must be fixed first to preserve morphology, then decalcified (using acid or chelating agents) to remove calcium salts before dehydration and paraffin processing can proceed.

Question 5

A technician notices that sections from a tissue block are crumbling during microtomy. The most likely processing error is:

Accepted Answer

Incomplete paraffin infiltration leaving residual clearing agent

Answer

Incomplete paraffin infiltration leaves clearing agent (e.g., xylene) in the tissue, which prevents proper wax support and causes sections to crumble or fragment during cutting.

(HTL) Histotechnology Certification Practice Test

(HTL) Histotechnology Certification Practice Test

HTL Tissue Processing & Fixation 3