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

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.

Too long: Will not have an effect on staining.

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.

Too long: Will obscure the target tissue.

 

Acid alcohol

Acts as a decolourizer

 

Omitted: Target tissue will be obscured.

 

Too short: Target tissue will be obscured.

 

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