What is acid fast staining?
Certain bacteria or their structures have the ability to retain the primary dye (strong carbol fuchsin) and resist decolourization by weak mineral acids such as H2SO4, HCl. Such bacteria or their structure are termed acid fast and this property is termed acid fastness. There are two types of acid fast staining, the hot method and the cold method. The hot method (Ziehl-Neelsen) involves heating the slide while the cold methods such as Kinyouns and Gabbetts do not involve heating the slide.
