HT Routine & Special Staining Methods 2

Question 1

In the Periodic Acid-Schiff (PAS) reaction, periodic acid acts by:

Accepted Answer

Oxidizing vicinal diols to aldehydes

Answer

Periodic acid oxidizes vicinal diol groups in polysaccharides to aldehydes, which then react with Schiff reagent to produce a magenta color.

Question 2

Which control tissue is most appropriate when validating a Gomori methenamine silver (GMS) stain for fungi?

Accepted Answer

Lung tissue with confirmed Aspergillus infection

Answer

Lung tissue with confirmed Aspergillus provides positive fungal organisms to verify that GMS is correctly staining fungal cell walls black.

Question 3

The Warthin-Starry stain is used primarily to demonstrate:

Accepted Answer

Helicobacter pylori and spirochetes

Answer

Warthin-Starry is a silver impregnation method that blackens spirochetes and organisms such as Helicobacter pylori against a yellow-brown background.

Question 4

In the Masson trichrome stain, the sequence of dyes applied after Weigert's iron hematoxylin is:

Accepted Answer

Biebrich scarlet-acid fuchsin, then phosphomolybdic/phosphotungstic acid, then aniline blue

Answer

After nuclear staining with Weigert's hematoxylin, cytoplasm/muscle is stained red with Biebrich scarlet-acid fuchsin, then collagen is differentiated and counterstained blue with aniline blue.

Question 5

Which reagent is used to differentiate (decolorize) background in the Ziehl-Neelsen acid-fast stain?

Accepted Answer

1% acid-alcohol

Answer

1% acid-alcohol removes carbol fuchsin from non-acid-fast elements, leaving only mycobacteria stained red.

(HT) Histotechnician Certification Practice Test

(HT) Histotechnician Certification Practice Test

HT Routine & Special Staining Methods 2