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

Standard overnight processing with no modification

Answer

Rapid microwave processing

Answer

Immediate frozen section embedding

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

It lowers the melting point of paraffin

Answer

It speeds up the dehydration process

Answer

It prevents tissue shrinkage

Question 3

Glutaraldehyde is the preferred fixative for electron microscopy because:

Accepted Answer

It provides superior ultrastructural preservation via extensive protein cross-linking

Answer

It penetrates tissue faster than formalin

Answer

It is non-toxic compared to formalin

Answer

It requires no buffer to maintain pH

Question 4

When processing bone specimens for histology, decalcification is performed:

Accepted Answer

After fixation and before dehydration

Answer

Before fixation to prevent cracking

Answer

After embedding in paraffin

Answer

Simultaneously with clearing

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

Over-fixation with formalin

Answer

Tissue placed in too-hot paraffin

Answer

Excessive dehydration time

Question 6

The pH of 10% neutral buffered formalin is maintained at approximately:

Accepted Answer

7.0–7.4

Answer

4.5–5.0

Answer

6.5–7.0

Answer

8.0–8.5

Question 7

Which of the following is a xylene substitute used in tissue processing to reduce toxicity exposure?

Accepted Answer

Clearene (d-limonene-based)

Answer

Acetone

Answer

Isopropanol

Answer

Methanol