MODIFICATIONS OF ACID-FAST STAINING

 The original method devised by Ziehl Neelsen employs implification of heat hence it is widely known as "Hot method." Later on, it was modified techniques were developed where heating is not required, this is known as "Cold method."

KINYOUN'S METHOD:

1. Flood the smear with Kinyoun's carbol fuchsin for 5 mins.
2. Decolourize with acid alcohol for 5 mins.
3. Add methylene blue for 4 mins.

GABBET'S METHOD (2 step method):

1. Flood the slide with basic fuchsin-phenol stain for 10 mins.
2. Counter stain with Gabbet's methylene blue(contains sulfuric acid) for 2 mins.