Comparison of Bronchoscopy and Gastric Washings in the Investigation of Smear-Negative Pulmonary Tuberculosis

This study compares the utility of gastric washings (GWs) and bronchoscopy in the diagnosis of smear-negative pulmonary tuberculosis (TB). The aim of the study was to identify which investigation or combination of investigations provided the greatest yield of positive Mycobacterium tuberculosis cultures of samples from patients with smear-negative pulmonary TB. We retrospectively analyzed the medical records of 180 patients with smear-negative pulmonary TB. The positive culture yield for bronchoalveolar lavage fluid (62 [34%] of 180 patients) was significantly greater than that for specimens from 3 GWs (32 [21%] of 149 patients) (P=.02). Combining GW and bronchoscopy increased the positive culture yield: bronchoscopy combined with 2 GWs resulted in a positive culture rate of 38%. Bronchoscopy is superior to GW in the diagnosis of smear-negative pulmonary TB; however, the combination of bronchoscopy and 2 GWs should be regarded as optimal for the diagnosis of smear-negative pulmonary TB.