The acid-fast staining process involves several steps: 1. Primary Stain: The tissue sample is stained with a primary stain, typically carbol fuchsin, which penetrates the lipid-rich cell wall of acid-fast bacteria. 2. Decolorization: The sample is then treated with an acid-alcohol solution. Non-acid-fast bacteria lose the primary stain and become decolorized, while acid-fast bacteria retain the stain. 3. Counterstain: A counterstain, such as methylene blue or malachite green, is applied to the sample. This stains the non-acid-fast bacteria and the background, providing contrast to the acid-fast bacteria, which remain bright red or pink.
