Abstract: Objective To evalute the diagnosis value of fiberoptic bronchoscopy(FB) in diffuse pulmonary diseases(DPD). Methods In the period of 1993～1999, 86 patients with DPD, who were negative sputum smears for tubercle bacilli and pathological examination for tumor, were received bronchoscopy, transbronchial biopsy, brushing and bronchoalveodar lavage(BAL). Results The overall positive rate of FB in DPD was 87.2%, 51 of 86 (59.4%) cases had lesions by immediate bronchoscopy identification, positive rate of transbronchial biopsy, brushing and BAL was 69.2% ,55.6% and 30.8%. Among 38 patients with lung cancer, the positive rates of bronchial neoplasm, lung biopsy were as high as 100% and 84.2%. On the other hand, the positive rates of BAL was only 27.3%. Among 25 patients with tuberculosis, The overall positive rate of biopsy was 85.7%, while positive rate of tubercle bacilli brushing and culture was only 16.2%. The shows that the positive rate of transbronchial lung biopsy was not increased with the number of biopsies. Conclusions Bronchoscopy, especially with biopsy ,is a safe, simple method which has a high diagnostic rate and less complications.

Key words: Fiberoptic bronchoscopy, diffuse pulmonary diseases, diagnosis