Aims: To evaluate a safe sputum processing method for detection of tuberculosis in developing countries.
Methods: A sample processing method was developed in which acid fast bacilli were killed with 1% sodium hypochlorite and concentrated by flotation on a layer of xylene before staining by the Ziehl Neelsen or auramine O methods.
Results: Best results were obtained by auramine O staining after flotation. Staining by the Ziehl Neelsen method after flotation gave better results than direct Ziehl Neelsen staining without flotation.
Conclusions: The flotation method with Ziehl Neelsen staining offers advantages for smear preparation in the tuberculosis control programmes of developing countries.