Auramine- Rhodamine Staining MCQs Mock Test (30 MCQs)

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Master Auramine-Rhodamine staining, the sensitive fluorescent technique for rapid acid-fast bacilli (AFB) screening in tuberculosis diagnosis. This guide covers:

✓ Dual-fluorochrome principle (Auramine O & Rhodamine B)
✓ CDC-approved protocol for sputum smears
✓ Key advantages over Ziehl-Neelsen staining:

10x higher sensitivity
Faster screening (40x vs 100x magnification)
Better for paucibacillary samples

✓ Microscopy interpretation:

Apple-green fluorescing rods = AFB
Red-orange counterstain = background

✓ Quality control measures
✓ Comparison with LED fluorescence microscopy

Essential for TB lab technicians, microbiologists, and public health workers in high-burden settings.

Test your TB diagnostics skills with 35+ Auramine-Rhodamine MCQs:
◼️ Principle of fluorochrome binding
◼️ Correct filter combinations
◼️ CDC grading criteria (1+ to 4+)
◼️ Biosafety considerations

Crucial for:

NTEP/RNTCP certification (India)
WHO TB laboratory training
MLS/MLT board exams

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Microbiology Department

Auramine- Rhodamine Staining MCQs Mock Test

Test your TB diagnostics skills with 30 Auramine-Rhodamine MCQs:
◼️ Principle of fluorochrome binding
◼️ Correct filter combinations
◼️ CDC grading criteria (1+ to 4+)
◼️ Biosafety considerations

Crucial for:

NTEP/RNTCP certification (India)
WHO TB laboratory training
MLS/MLT board exams

Read Full Article: Auramine- Rhodamine Staining FAQs and MCQs

1 / 30

Category: Clinical Laboratory

Why is heat fixation avoided during staining?

It destroys mycolic acid

None of the above

Fluorescent dyes bind strongly without heat

It makes the slide brittle

2 / 30

Category: Clinical Laboratory

How long should the primary stain (Auramine-Rhodamine) be applied?

5 minutes

30 minutes

1 minute

15 minutes

3 / 30

Category: Clinical Laboratory

How should acid-alcohol waste be disposed of?

Pour down the sink

Discard in regular trash

Treat as hazardous waste

Reuse for future staining

4 / 30

Category: Clinical Laboratory

What type of microscope is required for Auramine-Rhodamine staining?

Electron microscope

Light microscope

Phase-contrast microscope

Fluorescent microscope

5 / 30

Category: Clinical Laboratory

Which of the following is an advantage of Auramine-Rhodamine over ZN staining?

Requires oil immersion

More sensitive (~10% higher detection)

Takes longer to perform

Needs a light microscope

6 / 30

Category: Clinical Laboratory

How many fields should be examined before reporting a negative result at 400X magnification?

100

7 / 30

Category: Clinical Laboratory

What is the role of potassium permanganate in this staining?

Mordant

Counterstain (reduces background fluorescence)

Primary stain

Decolorizer

8 / 30

Category: Clinical Laboratory

What happens if the smear is too thick?

None of the above

AFB fluoresce brighter

The slide cracks

Decolorization may be incomplete (false positives)

9 / 30

Category: Clinical Laboratory

What is the recommended filter combination for fluorescence microscopy?

Brightfield condenser

K530 excitation + BG12 barrier

488 nm laser + DAPI filter

Phase-contrast ring

10 / 30

Category: Clinical Laboratory

Which organism may NOT fluoresce with this stain?

Mycobacterium tuberculosis

Sporozoan parasites

Rapid-growing Mycobacteria

Mycobacterium leprae

11 / 30

Category: Clinical Laboratory

Why is Auramine-Rhodamine staining more sensitive than Ziehl-Neelsen (ZN) staining?

It uses a higher magnification

It does not require heat fixation

Both b and c

Fluorescent bacilli are easier to detect

12 / 30

Category: Clinical Laboratory

Which component of Mycobacterium spp. binds to Auramine-Rhodamine dye?

Lipopolysaccharide

Peptidoglycan

Mycolic acid

Teichoic acid

13 / 30

Category: Clinical Laboratory

What does a pale yellow background indicate?

Positive for AFB

Over-decolorization

Contamination

Negative for AFB

14 / 30

Category: Clinical Laboratory

If AFB appear faint, what could be the reason?

All of the above

Insufficient staining time

Old reagents

Over-decolorization

15 / 30

Category: Clinical Laboratory

Why is culture still needed after a positive stain?

Culture is faster

Because staining is always wrong

To confirm AFB presence and perform drug susceptibility testing

None of the above

16 / 30

Category: Clinical Laboratory

Which organization recommends fluorochrome staining for AFB detection?

WHO

FDA

NIH

CDC

17 / 30

Category: Clinical Laboratory

A major limitation of Auramine-Rhodamine staining is:

Only works on blood samples

It is less sensitive than ZN staining

It cannot detect Mycobacterium spp.

b) Requires a fluorescent microscope

18 / 30

Category: Clinical Laboratory

What is the alternative staining method if a fluorescent microscope is unavailable?

Ziehl-Neelsen staining

India ink staining

Giemsa staining

Gram staining

19 / 30

Category: Clinical Laboratory

What PPE is required when handling these stains?

d) No PPE needed

Gloves and lab coat

Both a and b

b) Goggles and fume hood

20 / 30

Category: Clinical Laboratory

What is the major drawback of potassium permanganate?

It is non-toxic

It is a skin/eye irritant

It enhances fluorescence

It stabilizes the stain

21 / 30

Category: Clinical Laboratory

What is the primary purpose of Auramine-Rhodamine staining?

To visualize viral particles

To identify fungal hyphae

To detect acid-fast bacilli (AFB)

To stain Gram-positive bacteria

22 / 30

Category: Clinical Laboratory

Which reagent in Auramine-Rhodamine staining is a possible carcinogen?

Potassium permanganate

Distilled water

Auramine O

Glycerol

23 / 30

Category: Clinical Laboratory

Why is distilled water preferred over tap water for rinsing?

None of the above

Distilled water dries faster

Tap water is too expensive

Chlorine in tap water quenches fluorescence

24 / 30

Category: Clinical Laboratory

Which specimen is NOT suitable for Auramine-Rhodamine staining?

Sputum

Tissue sections

Blood smear

Urine sediment

25 / 30

Category: Clinical Laboratory

Which reagent acts as the decolorizer in Auramine-Rhodamine staining?

Crystal violet

Acid-alcohol

Safranin

Methylene blue

26 / 30

Category: Clinical Laboratory

How should a negative result be confirmed?

Use Ziehl-Neelsen staining

Discard the slide

Repeat Auramine-Rhodamine staining

Report as negative without confirmation

27 / 30

Category: Clinical Laboratory

What happens if the counterstain (potassium permanganate) is left too long?

Background becomes too dark

Fluorescence is quenched

The slide dissolves

AFB fluoresce brighter

28 / 30

Category: Clinical Laboratory

A positive Auramine-Rhodamine stain shows AFB as:

Reddish-orange fluorescent rods

Blue rods

Green cocci

Purple spirals

29 / 30

Category: Clinical Laboratory

What color do acid-fast bacilli (AFB) appear under fluorescence?

Blue

Bright yellow/orange

Green

Purple

30 / 30

Category: Clinical Laboratory

Why must slides be examined within 24 hours?

The slide disintegrates

None of the above

The stain becomes toxic

Fluorescence fades over time

Your score is

The average score is 70%

Read Full Article: Auramine- Rhodamine Staining FAQs and MCQs

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