Grocott-Gomori’s Methenamine Silver Staining

Explore Grocott-Gomori’s Methenamine Silver (GMS) Staining, a key histopathological technique used to detect fungal infections (e.g., Pneumocystis, Aspergillus, Candida) and some basement membrane components. This guide covers its principle, procedure, interpretation, and clinical significance—essential for pathologists, microbiologists, and lab professionals.

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Grocott-Gomori’s Methenamine Silver Staining MCQs Mock Test

Read Full Article: Grocott-Gomori’s Methenamine Silver Stain 50 FAQ and 40 MCQs

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Category: Clinical Laboratory

What indicates proper silver impregnation?

Slides turn red

Slides turn yellowish-brown

Slides become transparent

Slides turn blue

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Category: Clinical Laboratory

How are hyphae visualized in GMS?

Blue walls, clear interiors

Black walls, pink interiors

Unstained

Red walls, green interiors

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Category: Clinical Laboratory

What causes tissue to detach during staining?

Over-oxidation

Insufficient dehydration

Skipping the gold step

Using tap water

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Category: Clinical Laboratory

Which fungus is commonly detected using GMS in immunocompromised patients?

Herpes simplex virus

Pneumocystis jiroveci

Escherichia coli

Mycobacterium tuberculosis

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Category: Clinical Laboratory

Which counterstain is used in GMS to highlight the background?

Methylene blue

Hematoxylin

Light green SF yellowish

Eosin

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Category: Clinical Laboratory

What is the role of sodium metabisulfite in GMS?

Counterstain

Toning agent

Oxidizing agent

Reducing agent

7 / 30

Category: Clinical Laboratory

How long can methenamine silver stock solution be stored?

1 year

Indefinitely

3 months (refrigerated)

1 week

8 / 30

Category: Clinical Laboratory

Which reagent tones the sections to improve contrast?

Borax

Silver nitrate

Light green

Gold chloride

9 / 30

Category: Clinical Laboratory

What does mucin look like in GMS-stained sections?

Black

Pink-red

Dark grey

Green

10 / 30

Category: Clinical Laboratory

What color do fungi appear after GMS staining?

Green

Blue

Black

Red

11 / 30

Category: Clinical Laboratory

Which chemical oxidizes polysaccharides in GMS staining?

Sodium thiosulfate

Methenamine

Gold chloride

Chromic acid

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Category: Clinical Laboratory

What indicates a successful GMS control slide?

Clear unstained fungi

Uniform green background

Blue nuclei

Black fungal elements

13 / 30

Category: Clinical Laboratory

Why is borax added to the silver solution?

Prevents precipitation

Accelerates oxidation

Lowers pH

Acts as a buffer

14 / 30

Category: Clinical Laboratory

What hazard is associated with chromic acid?

Corrosive and carcinogenic

Radioactive

Flammable

Explosive

15 / 30

Category: Clinical Laboratory

What is the primary purpose of GMS staining?

Identifying fungal cell walls

Highlighting collagen fibers

Detecting bacterial infections

Staining viral particles

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Category: Clinical Laboratory

What is the purpose of sodium thiosulfate?

Enhance gold toning

Oxidize fungi

Remove unbound silver

Counterstain nuclei

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Category: Clinical Laboratory

Which step is skipped in microwave GMS vs. conventional?

None—steps are identical

Chromic acid oxidation

Gold toning

Silver incubation

18 / 30

Category: Clinical Laboratory

Why might fungi fail to stain black?

Old chromic acid

Excessive gold toning

Insufficient dehydration

Overuse of light green

19 / 30

Category: Clinical Laboratory

Which stain is more sensitive for fungi than GMS?

Gram stain

None—GMS is the most sensitive

H&E

PAS (Periodic Acid-Schiff)

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Category: Clinical Laboratory

How long should slides remain in chromic acid (conventional method)?

1 hour

2 hours

30 minutes

5 minutes

21 / 30

Category: Clinical Laboratory

What is a drawback of microwave GMS?

Longer procedure

Inconsistent heating

Weaker staining

Higher cost

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Category: Clinical Laboratory

Which step is unique to microwave GMS staining?

Overnight incubation

Using a water bath

Freezing slides

Heating chromic acid for 2.5 minutes

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Category: Clinical Laboratory

How long is chromic acid microwaved in the modified protocol?

10 minutes

2.5 minutes

1 hour

30 seconds

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Category: Clinical Laboratory

Why use plastic Coplin jars in microwave GMS?

Faster heating

Better staining

Prevents metal interference

Cheaper than glass

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Category: Clinical Laboratory

How should silver nitrate waste be handled?

Dispose as hazardous waste

Incinerate immediately

Pour down the sink

Reuse for future stains

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Category: Clinical Laboratory

Which organism is GMS-negative?

Toxoplasma gondii

Candida

Aspergillus

Histoplasma

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Category: Clinical Laboratory

Which fixative is optimal for GMS?

10% formalin

Acetone

Bouin’s solution

95% ethanol

28 / 30

Category: Clinical Laboratory

What wattage is used for microwave silver incubation?

1000W

450W

50W

150W

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Category: Clinical Laboratory

Which PPE is mandatory for GMS staining?

No special precautions

Gloves only

Lab coat and gloves

Goggles, gloves, lab coat, fume hood

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Category: Clinical Laboratory

Which component of the fungal cell wall reacts with GMS stain?

Lipids

Polysaccharides

Nucleic acids

Proteins

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Read Full Article: Grocott-Gomori’s Methenamine Silver Stain 50 FAQ and 40 MCQs

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