Diagnostic Yield of AFB smear and GeneXpert on Bronchial Washings with Fiber-Optic Bronchoscope in Patients with Sputum-Negative Pulmonary Tuberculosis
DOI:
https://doi.org/10.51985/Abstract
Objective: To determine and compare the diagnostic yield of acid-fast bacilli (AFB) smear microscopy and GeneXpert testing performed on bronchial washings in patients clinically suspected of pulmonary tuberculosis (PTB) but negative for both sputum AFB smear and GeneXpert. The study also aimed to evaluate the utility of bronchoscopic sampling as an adjunct diagnostic tool in sputum-negative PTB, where conventional methods often fail to confirm the diagnosis. Study Design and Setting: A descriptive cross-sectional study conducted at the Department of Pulmonology, Mayo Hospital, Lahore, from 7 March 2025 to 10 June 2025.
Methods: Patients aged 18–65 years with clinical and radiological evidence suggestive of PTB but negative sputum AFB smear and GeneXpert results were included. Bronchial washings were obtained through fiber-optic bronchoscopy and analyzed using Ziehl–Neelsen staining and GeneXpert MTB assay. Statistical analysis was performed using SPSS version 27, and diagnostic yields were compared.
Results: A total of 95 patients were enrolled, with a mean age of 35.49 ± 11.03 years. Of these, 53.7% were males and 65.3% were non-smokers. GeneXpert detected Mycobacterium tuberculosis in 85.3%, while AFB smear was positive in 56.8% of bronchial wash samples. GeneXpert showed a higher diagnostic yield compared to AFB smear in sputum-negative PTB cases.
Conclusion: GeneXpert testing of bronchial washings markedly enhances the diagnostic yield for sputum-negative PTB and should be incorporated as a routine diagnostic tool in patients with strong clinical and radiological suspicion of tuberculosis despite negative sputum findings.
Keywords: Bronchoscopy, Bronchial lavage, Pulmonary tuberculosis, Sputum
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