Bronchial Washing to Diagnose Smear-Negative Pulmonary Tuberculosis

Introduction: Bronchoscopy with bronchial washing is useful for the diagnosis of pulmonary tuberculosis (TB) when sputum smears are negative. However, its indication has not been standardized. Therefore, we conducted a retrospective study to assess the diagnostic value of bronchial washing in patients suspected with pulmonary TB. Methodology: A retrospective analysis was performed on patients diagnosed with pulmonary TB in Kosin university gospel hospital, a tertiary hospital with 969 beds in South Korea, from March 2017 to December 2018. We obtained three serial sputum samples for acid-fast bacilli (AFB) smear and culture, and all patients underwent bronchoscopy with bronchial washing for AFB smear and culture. Results: Fifty-six patients were enrolled in the study. Smear-negative pulmonary TB (SNPT) was diagnosed in 42/56 (75%) patients. Among the patients with smear-positive sputum, 14/14 (100%) showed culture-positive sputum, while smear- and culture-positive bronchial washing were seen in 7/14 (50%) and 12/14 (85.7%) patients, respectively. Among the patients with SNPT, 17/42 (40.47%) had culture-negative sputum and were diagnosed using the bronchoscopic washing. Conclusions: For patients with smear-negative sputum, it is necessary to perform bronchoscopic washing to increase the diagnostic rate of pulmonary TB. To control the transmission of pulmonary TB, it is necessary to use a fast and accurate examination method.