Merck, 21819-50ML-F, Carbol-Fuchsin solution according to Kinyoun

General description
Carbol-Fuchsin is an acid-fast stain that consists of basic fuchsin and phenol. It is a dry staining dye for staining acid-fast bacteria such as Mycobacterium tuberculosis. Carbol-Fuchsin solution according to Kinyoun is a modified stain that does not require heat to infuse the carbol-fuchsin into the acid-fast cells during the staining process, and this process is also known as “cold staining”. It requires a higher concentration of the primary stain.
Application
Kinyoun’s carbol-fuchsin is intended for use to stain paraffin sections of a formaldehyde-fixed specimen containing tubercle bacilli, and for the demonstration of tuberculosis bacteria (Mycobacterium tuberculosis).
It is also applicable for other organisms that retain the dye after immersion in acidified 70% alcohol.
It has been used to develop a staining technique for detecting microsporidial spores in fecal specimens.

Biochem/physiol Actions
Acid-fast bacteria possess a waxy, lipid-rich cell wall that absorbs dyes very slowly. To enhance the absorption of carbol-fuchsin dye and the subsequent formation of the mycolate-fuchsin complex, the dye solution applied to the specimen is normally heated to the evaporation point. In Kinyoun’s modification of this method, the heating of the solution is avoided. Consequently, hazardous phenolic vapors are not released.
Other Notes
Stain used for the demonstration of tuberculosis bacteria