for Acid Alcohol Fast Bacteria


Fite's carbol–new fuchsin
Acidified Harris' hemalum
Fite's picro fuchsin
20% aqueous formalin (1 in 5 dilution of strong formalin)
2% hydrochloric acid in 95% ethanol
1% aqueous potassium permanganate
2% aqueous oxalic acid

Tissue sample
Formal alcohol was recommended but 5µ paraffin sections of neutral buffered formalin fixed tissue are likely suitable.


  1. Bring sections to water via xylene and ethanol.
  2. Place sections in carbol-new fuchsin overnight.
  3. Place in 20% formalin for 5 minutes.
  4. Decolorise in 2% acid alcohol for 5 minutes.
  5. Rinse with water.
  6. Place in 1% potassium permanganate for 2-5 minutes.
  7. Bleach with 2% oxalic acid for 1 minute.
  8. Wash with water.
  9. Counterstain with Harris' hemalum for 2 minutes.
  10. Wash with water.
  11. Stain with Fite's picro-fuchsin until adequately stained.
  12. Dehydrate with 95% and absolute ethanols.
  13. Clear with xylene and mount with a resinous medium.

Expected results


  1. Harris' hemalum should contain acetic acid at 50 mL per litre.
  2. Note that Fite's method is not meant to be specific for M. leprae. It is for acid alcohol fast organisms.
  3. This method was modified by Wade by dewaxing in a mixture of 2 parts rectified turpentine and 1 part liquid paraffin applied twice for 5 minutes each, then blotted and washed repeatedly until the tissue is wetted by the washing. Despite this, the Wade-Fite stain is usually given as this one.


Gray, Peter. (1954)
The Microtomist's Formulary and Guide.
Originally published by:– The Blakiston Co.
Republished by:– Robert E. Krieger Publishing Co.

Humason, G.L., (1967)
Animal Tissue Techniques
W.H. Freeman & Co., San Francisco, CA, USA




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