ASCP Special Stains and Histochemistry

Question 1

What does the PAS (Periodic Acid-Schiff) stain primarily identify?

Accepted Answer

Glycogen, neutral mucins, and basement membranes

Answer

PAS stains 1,2-glycol groups in polysaccharides, glycoproteins, and mucins magenta-red by oxidizing them with periodic acid and then applying Schiff reagent.

Question 2

In a Masson's trichrome stain, what color does collagen appear?

Accepted Answer

Blue or green

Answer

Masson's trichrome stains collagen blue (or green in the Goldner variant), muscle red, and nuclei dark brown-black.

Question 3

Which special stain is used to identify iron (hemosiderin) deposits in tissue?

Accepted Answer

Prussian blue (Perl's stain)

Answer

Perl's Prussian blue reacts ferric iron with potassium ferrocyanide to produce a bright blue precipitate at iron deposition sites.

Question 4

What is the characteristic staining result of amyloid with Congo red?

Accepted Answer

Apple-green birefringence under polarized light

Answer

Amyloid stained with Congo red shows salmon-pink color in brightfield and apple-green birefringence under polarized light.

Question 5

Which stain is used to identify fungi and mucin simultaneously in tissue sections?

Accepted Answer

Both GMS and PAS

Answer

Both GMS and PAS are effective for identifying fungal organisms; GMS turns fungi black, while PAS stains them magenta.

ASCP - Histotechnician Test Practice Test

ASCP - Histotechnician Test Practice Test

ASCP Special Stains and Histochemistry