Diagnostic Accuracy of BD MAX MDR-TB Assay Performed on Bronchoscopy Specimens in Patients with Suspected Pulmonary Tuberculosis

Background: Several novel molecular platforms using nucleic acid amplification tests have been developed for the diagnosis of pulmonary tuberculosis (PTB) and rapid detection of isoniazid and rifampin resistance. Among them, the BD MAX MDR-TB assay (BD MAX) has shown high sensitivity and specificity; however, its diagnostic accuracy performed on bronchoscopy specimens has not been reported. Methods: We retrospectively reviewed the medical records of patients with suspected PTB who underwent bronchoscopy. Patients who underwent BD MAX testing of bronchoscopy specimens were included in the final analysis. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for PTB diagnosis were calculated using a positive culture of Mycobacterium tuberculosis as the reference standard. Results: Of 114 patients, 34 had culture-confirmed PTB. The sensitivity, specificity, PPV, and NPV of BD MAX performed on bronchoscopy specimens for the diagnosis of PTB were 79.4%, 88.8%, 75.0%, and 91.0%, respectively. The sensitivity of BD MAX was superior to that of acid-fast bacillus smear (79.4% vs. 38.2%, p<0.001). Conclusion: BD MAX performed on bronchoscopy specimens showed high accuracy for diagnosing PTB. BD MAX can be performed on bronchoscopy specimens in patients with suspected PTB.