Description
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 identifies acid-fast bacteria by their retention of carbolfuchsin,the primary stain, despite acid-alcohol decolorization, allowing for rapid, visual diagnosis primarily of TB and related infections. Non-acid-fast bacteria and other cells take upmethylene blue, the counterstain, providing contrast.
Indications
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
Negative