HTL Tissue Processing & Fixation 2

Question 1

During tissue processing, the graded alcohol series typically ends at which concentration before clearing?

Accepted Answer

100% (absolute) ethanol

Answer

Tissue must pass through 100% (absolute) ethanol as the final dehydration step to ensure complete water removal before the clearing agent is introduced.

Question 2

What is the optimal paraffin infiltration temperature range used in automated tissue processors?

Accepted Answer

50–60°C

Answer

Paraffin infiltration is performed at 50–60°C, just above the melting point of standard embedding paraffin, ensuring the wax remains liquid for infiltration without damaging tissue.

Question 3

A tissue specimen shows shrinkage artifact and poor nuclear detail after processing. The most likely cause is:

Accepted Answer

Excessive dehydration time in high-concentration alcohol

Answer

Prolonged exposure to high-concentration alcohol causes protein denaturation and excessive tissue shrinkage, resulting in poor morphology and nuclear detail.

Question 4

Which embedding medium is used for frozen sections when rapid diagnosis is required?

Accepted Answer

Optimal cutting temperature (OCT) compound

Answer

OCT compound is the standard embedding medium for frozen sections because it provides support for cryostat cutting at low temperatures without requiring chemical processing.

Question 5

The fixative Bouin's solution is best suited for which type of tissue?

Accepted Answer

Testicular and gastrointestinal biopsies

Answer

Bouin's solution (picric acid, formalin, acetic acid) is preferred for testicular and gastrointestinal biopsies because it provides excellent nuclear detail and cytoplasmic preservation.

(HTL) Histotechnology Certification Practice Test

(HTL) Histotechnology Certification Practice Test

HTL Tissue Processing & Fixation 2