[The usefulness of induced sputum in the diagnosis of pulmonary tuberculosis].

This study was designed to compare the results of culture for tubercle bacilli using induced sputum by an ultrasonic nebulizer and gastric aspirates from same patients who were suspected of having active tuberculosis with little or no sputum and had received no prior chemotherapy. 22 patients included in this series were either culture positive for tubercle bacilli or showed unequivocal radiographic improvement after three months of therapy with three anti-tuberculosis drugs. Induced sputum from 17 patients and gastric aspirates from seven patients were culture positive for M.tuberculosis. This difference is significant (p < 0.01). Paired induced sputum and gastric aspirates were both positive for tubercle bacilli in seven patients. The finding of acid-fast bacilli on microscopy or tubercle bacilli in culture in four of the seven patients were available much earlier with induced sputum than with gastric aspirates. Positive gastric aspirates and negative induced sputum for tubercle bacilli was not seen. These results suggest that induced sputum by an ultrasonic nebulizer is superior to gastric aspirates in terms of high sensitivity and early finding for tubercle bacilli and induced sputum and gastric aspirates do not supplement each other.