IMPROVED MICROSCOPIC DIAGNOSIS OF PULMONARY TUBERCULOSIS IN DEVELOPING-COUNTRIES

The diagnosis of pulmonary tuberculosis (TB) relies on the bacteriolog ical examination of sputum. However, microscopy of smears made directl y from sputum has a low sensitivity and there is an urgent need for im proved methods. We have compared microscopy of smears made directly fr om sputum with microscopy after liquefaction of sputum with household bleach (NaOCl) and concentration of bacteria by centrifugation. In 3 s tudies performed in Ethiopia and India, the use of the NaOCl method in creased the number of samples positive for acid-fast bacilli by more t han 100%. The technique is appropriate for developing countries and it s application would increase the efficiency of TB control programmes. As a potent disinfectant, NaOCl also has the advantage of lowering the risk of laboratory infection.