1. Lab Exercise 7:
Acid Fast Staining

2. Kinyoun Acid-Fast Staining Procedure
Carbol fuchsin
Acid alcohol
Methylene blue
Reddish-pink
Blue
Acid Fast
Nonacid Fast
Kinyoun Acid-Fast Staining Procedure
1. A sample of cells is mixed with a drop of water on a clean slide to make a smear. After air drying, the slide is heat fixed.
2. Slide is flooded with carbol fuchsin (primary stain basic fuchsin + mordant carbolic acid) and allowed to sit for 15 minutes.
Slide is rinsed until water coming off the slide is clear.
3. Slide is decolorized with acid alcohol (3% HCl and 95% alcohol) 20 seconds, then rinsed.
4. Slide is flooded with methylene blue (counter stain) for 60 seconds and then rinsed.

3. Note the reddish-pink color and “cording” (sticking together in long ropy masses) of the Mycobacterium cells due to the excess lipids of the cell wall

4. Identify the following in this sputum smear:
Epithelial cell (E), Streptococcus mutans (S), Mycobacterium tuberculosis (M) M S E

5. Locate Mycobacterium tuberculosis (M)

6. Put these solutions in order of their use in the Kinyoun acid-fast staining procedureB C
Answer: C, B, A