Acid Fast Stain (Kinyoun-Cold Method)- Principle, Procedure and Result Interpretation


The Kinyoun-Cold Method is a staining technique that is used to identify acid-fast microorganisms, such as Mycobacterium spp. and some parasites, such as Cryptosporidium and Isopora spp. Acid-fast microorganisms are those that retain the primary stain, carbolfuchsin, even after being treated with a decolorizing agent, such as sulfuric acid. This property is due to the presence of mycolic acid in their cell walls, which makes them resistant to staining with water-based dyes.

Acid-fast staining is important for the diagnosis and treatment of various diseases caused by acid-fast microorganisms, such as tuberculosis, leprosy, nocardiosis, and cryptosporidiosis. The Kinyoun-Cold Method is a modification of the Ziehl-Neelsen Method, which requires heating the specimen during staining. The Kinyoun-Cold Method does not require heating, but uses a more concentrated solution of carbolfuchsin and phenol to penetrate the cell wall of acid-fast microorganisms. The Kinyoun-Cold Method is also faster and simpler than the Ziehl-Neelsen Method, making it suitable for routine laboratory use.