Department of Clinical Laboratory, The Fifth People's Hospital of Suzhou, Infectious Disease Hospital Affiliated to Soochow University, No. 10, Guangqian Road, Xiangcheng District, Suzhou 215000, China; National Clinical Laboratory on Tuberculosis, Beijing Chest Hospital affiliated to Capital Medical University, Beijing Tuberculosis and Thoracic Tumor Research Institute, No 9, Beiguan Street, Tongzhou District, Beijing 101149, China. Electronic address: [Email]
OBJECTIVE : We prospectively evaluated the use of bronchoalveolar lavage fluid (BALF) specimens to assess their added incremental value to pulmonary tuberculosis (TB) diagnostic strategies used currently in a high-burden urban setting in China. METHODS : A prospective study was conducted of patients with presumptive pulmonary TB registered at the Fifth Hospital of Suzhou between March 2018 and July 2018. BALF samples from patients with initial Xpert-negative sputum results were tested to diagnose TB. RESULTS : Of 440 participants, 316 (71.8%) were initially diagnosed with TB from sputum, including 245 (55.7%) definitive TB cases based on a positive culture and/or Xpert result(s) and 71 (16.1%) positive cases based on clinical diagnosis. Of 153 patients with initial positive cultures, a significantly higher proportion were confirmed as TB-positive using Xpert (94.1%) versus smear microscopy (45.8%, P < 0.01). Xpert testing of BALF from 182 Xpert-negative cases exhibited greater detection sensitivity (97.4%) than did smear microscopy (23.4%, P < 0.01). Meanwhile, 74.1% of TB patients initially diagnosed as TB-negative via smear microscopy were identified using Xpert testing of BALF at reduced diagnostic cost/patient (from USD 266.9 to 171.5). CONCLUSIONS : BALF samples added incremental value to pulmonary TB diagnostic strategies for patients with Xpert-negative sputum. Xpert outperformed smear microscopy for tubercle bacilli detection in both sputum and BALF.