Ziehl Neelson
Classification: acid-fast bacteria stain
Mechanism of staining: ionic bonding
Purpose: stain Mycobacterium tuberculosis
Control tissue: infected lung tissue
Properly Stained Slide
Tubercle bacilli: red
Cytoplasm: pale blue
Nuclei: blue
RBCs: pale pink
REAGENT |
PURPOSE |
MECHANISM OF STAINING |
SOURCE OF ERROR |
Carbol fuchsin |
Stains Mycobacterium tuberculosis infections. |
Ionic bonding |
Omitted: Mycobacterium tuberculosis bacterium will not
be demonstrated. |
Too short: Mycobacterium tuberculosis bacterium will not
be demonstrated or weakly stained. |
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Too long: Will not have an effect on staining. |
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Methylene blue |
Is the counterstain, which stains the nuclei and cytoplasm |
Ionic bonding |
Omitted: Nuclei and cytoplasm will not be demonstrated. |
Too short: Nuclei and cytoplasm will not be demonstrated or
weakly stained. |
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Too long: Will obscure the target tissue. |
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Acid alcohol |
Acts as a decolourizer |
|
Omitted: Target tissue will be obscured. |
|
Too short: Target tissue will be obscured. |
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|
Too long: Primary stain and counterstain will be affected and
removed. |
Reference
Officer B. HIML251 Lecture notes: Gram and Gram Twort Stains and Ziehl Neelsen Technique, February 4, 2009