Special Stains and Histochemistry Flashcards
6 cards from real ASCP practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Special Stains and Histochemistry flashcards as text
What does the PAS (Periodic Acid-Schiff) stain primarily identify?
Answer: Glycogen, neutral mucins, and basement membranes
PAS stains 1,2-glycol groups in polysaccharides, glycoproteins, and mucins magenta-red by oxidizing them with periodic acid and then applying Schiff reagent.
In a Masson's trichrome stain, what color does collagen appear?
Answer: Blue or green
Masson's trichrome stains collagen blue (or green in the Goldner variant), muscle red, and nuclei dark brown-black.
Which special stain is used to identify iron (hemosiderin) deposits in tissue?
Answer: Prussian blue (Perl's stain)
Perl's Prussian blue reacts ferric iron with potassium ferrocyanide to produce a bright blue precipitate at iron deposition sites.
What is the characteristic staining result of amyloid with Congo red?
Answer: Apple-green birefringence under polarized light
Amyloid stained with Congo red shows salmon-pink color in brightfield and apple-green birefringence under polarized light.
Which stain is used to identify fungi and mucin simultaneously in tissue sections?
Answer: Both GMS and PAS
Both GMS and PAS are effective for identifying fungal organisms; GMS turns fungi black, while PAS stains them magenta.
What is the purpose of using a diastase control with a PAS stain?
Answer: To confirm that PAS-positive material is glycogen by removing it with diastase pretreatment
Diastase digests glycogen; if PAS positivity disappears after diastase treatment, the material was glycogen rather than other PAS-positive substances.