It has been shown that AFB in sputum samples can be killed within 30 min by phenol ammonium sulphate solution (3) and that they can be stained in sputum containers by 1 per cent carbol-fuchsin solution (4).
The concentrations of phenol and basic-fuchsin (in standard ZN method, carbol-fuchsin solution contains 5 % phenol and 1% basic-fuchsin) in phenol ammonium sulphate basic fuchsin solution were doubled in order to maintain sufficient concentrations when added to sputum samples.
If the sputum can be stained in its container, this technique will have following advantages to mycobacteriologists and medical technologists working in sputum AFB microscopy centres all over the world: (i) Risk of acquired infection can be reduced as the sputum treated with phenol ammonium sulphate carbol-fuchsin solution is sterile.
Specimens were processed routinely and stained with haematoxylin and eosin; the first 125 specimens with Fite-Faraco stain, and the other 75 specimens with a modified Fite-Faraco stain using carbol-fuchsin solution
to stain acid-fast bacilli, Weigert's iron haematoxylin to stain nuclei, and metanil yellow solution to stain other tissue elements.