Test : Acid Fast stain
Indications : The staining is used to detect the presence of mycobacteria, monitor therapy against mycobacterium, efective diagnosis of mycobacterial infection.
Physiology : Acid fast bacteria are surrounded by a waxy envelope that is resistant to destaining by acid alcohol. Heat, prolonged exposure peneterates the cell wall. The stained bacteria is resistant to decolorization with acid alcohol.
Normal Range : No acid fast bacteria. Positive smears are quantitated and reported as 1+ (3-9 bacteria in entire smear), 2+ (>10 in entire smear), or 3+ (1 or more bacilli per field) acid fast bacteria seen.
Sample : Fluid, pus, or abscess material
Test Method : Acid fast stain - Ziehl-Neelsen or fluorochrome stain
Related Tests : Mycobacteria by DNA probe, Skin Test, Tuberculosis.
why do u heat at intervals during acid fast stain.