Abstract: Objective To determine the diagnostic value of fibrebronchoscope on diagnosis bacteriological negative tuberculosis at lower part lung.Methods Retrospective analysis on the clinical information of 60 bacteriological negative tuberculosis cases confirmed by fibrebronchoscope who were misdiagnosed.Results Most of the cases suffered with catarrh at middle and lower part of bronchuswhich was 25 cases (41.7%) and 20 cases (33.3%) respectively.7 cases suffered with nozzle stricture (11.7%).37 cases (61.7%) with positive bacteriological result confirmed by merely brush examining.46 cases (76.7%) with positive result through brush examining and bronchus alveolus lavage.Fifty-two cases were diagnosed as tuberculosis through BAL and phlegm test after fibrebronchoscope and tissue live test.Sixty cases were diagnosed as tuberculosis by combination of the 4 mehtods (100%).Conclusion Fibrebronchoscope could improve the accurate diagnosis rate of tuberculosis at lower part of lung.Brush examining,bronchus alveolus lavage (BAL),tissue live test and phlegm test after fibrebronchoscope are supplementary for improving the diagnosis rate and avoiding misdiagnose.

Key words: Pulmonary tuberculosis/diagnose, Fibrebronchoscope, Misdiagnose