The acid-fast stain is a lab test that shows if bacteria that cause tuberculosis (TB) and other diseases are present in a sample of tissue, blood, or other body fluid.
There was once a lot of TB. But it doesn’t happen much anymore in the United States. In 2014, only 3 cases of tuberculosis were reported for every 100,000 people in the United States, according to the Centers for Disease Control and Prevention (CDC).
More About Acid-Fast Stain
Acid-fast stain is used to find organisms like those in the genus Mycobacterium that don’t change color when exposed to acid. Acid-fast organisms have cell walls that are waxy and almost impossible to break through. They also have a lot of mycolic acid and fatty acids, waxes, and complex lipids. Because this kind of cell wall is resistant to most chemicals, acid-fast organisms need a special way to stain.
Carbol fuchsin is the main stain used for acid-fast staining. It dissolves in fats and contains phenol, which helps the stain get into the cell wall. This process is helped even more by adding heat in the form of heat (steam). Steam helps break up the waxy layer and makes it easier for the main stain to get into the cell. The smear is then rinsed with a very strong decolorizer, which removes the stain from all cells that are not acid-fast but does not go through the cell walls of organisms that are acid-fast. The non-acid-fast cells that had lost their color then took up the counterstain, which was methylene blue in this case.
Also read: Aesthenia