Auramine phenol stain is a

stain A stain is a discoloration that can be clearly distinguished from the surface, material, or medium it is found upon. They are caused by the chemical or physical interaction of two dissimilar materials. Accidental staining may make materials ap ...

used in clinical

microbiology Microbiology () is the scientific study of microorganisms, those being unicellular (single cell), multicellular (cell colony), or acellular (lacking cells). Microbiology encompasses numerous sub-disciplines including virology, bacteriology, ...

and

histology Histology, also known as microscopic anatomy or microanatomy, is the branch of biology which studies the microscopic anatomy of biological tissues. Histology is the microscopic counterpart to gross anatomy, which looks at larger structures v ...

to identify

tuberculosis Tuberculosis (TB) is an infectious disease usually caused by '' Mycobacterium tuberculosis'' (MTB) bacteria. Tuberculosis generally affects the lungs, but it can also affect other parts of the body. Most infections show no symptoms, ...

mycobacteria ''Mycobacterium'' is a genus of over 190 species in the phylum Actinomycetota, assigned its own family, Mycobacteriaceae. This genus includes pathogens known to cause serious diseases in mammals, including tuberculosis ('' M. tuberculosis'') and ...

. There are two types of auramine phenol stains, 1 and 2 to stain mycobacterium species and cryptosporidium respectively. Both are

fluorescent Fluorescence is the emission of light by a substance that has absorbed light or other electromagnetic radiation. It is a form of luminescence. In most cases, the emitted light has a longer wavelength, and therefore a lower photon energy, ...

stains. The bacteria or the parasites appear brilliant greenish yellow against dark background. Mycolic acids of the mycobacteria keep this stain when decolorising with the acid alcohol. The method is more rapid and sensitive than ZN technique.

Method

* Smears are prepared just like that for ZN staining * Stain with Auramine-Phenol for 20 mins * Rinse with water * Decolourise in acid alcohol * Rinse with water * Counterstain with 0.1% potassium permanganate for 30 seconds * Rinse and air dry

References

Staining Tuberculosis {{Tuberculosis