The Kinyoun method, or Kinyoun stain, is an acid-fast procedure used to stain any species of the genus Mycobacterium and Nocardia[1] species. It involves the application of a primary stain (carbol fuchsin), a decolorizer (acid-alcohol), and a counterstain (methylene blue).[2] Unlike the Ziehl-Neelsen stain (Z-N stain), the Kinyoun method of staining does not require heating.[3][4] In the Ziehl-Neelsen stain, heat acts as a physical mordant while phenol (carbol of carbol fuschin) acts as the chemical mordant. Since the Kinyoun stain is a cold method (no heat applied), the concentration of carbol fuschin used is increased. [5]
