Ziehl-Nielsen (ZN) Stain for Acid-Fast Bacteria


The Ziehl-Nielsen (ZN) stain, also known as the acid-fast stain, was first described by two German doctors; Franz Ziehl and Friedrich Nielsen. The reagents used are Ziehl-Nielsen carbolfuchsin, acid alcohol and methylene blue.


ZN stain is a special bacteriological stain used to identify acid-fast organisms, mainly Mycobacteria. Mycobacterium tuberculosis is the most important of this group, as it is responsible for the disease called tuberculosis (TB). It can also be used to stain other bacteria such as Nocardia.

Sample Type, Quantity & Conditions

From the Corresponding Site Room Temperature

Special Precautions

Use the same specimen as for the culture of the corresponding site.

Normal Range


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