Abstract:

Objective: To determine the diagnostic accuracy of a nanopore sequencing assay for testing of bronchoalveolar lavage fluid (BALF) samples from suspected pulmonary tuberculosis (PTB) patients. Methods: Fifty cases with suspected PTB from Beijing Chest Hospital from November 2021 to April 2022 were collected. These cases were diagnosed based on results of MGIT 960 culture, GeneXpert MTB/RIF testing and nanopore sequencing of BALF samples collected during hospitalization. Taking the final clinical diagnosis as the reference standard, diagnostic accuracies of the three assays were compared. Results: Among the 50 cases analysed in this study, 22 (44.0%) were diagnosed as tuberculosis, 10 (20.0%) non-tuberculous mycobacteria and 18 (36.0%) bacterial pneumonia. Taking the clinic diagnosis as the reference standard, the sensitivity of nanopore sequencing assay technology, MGIT 960 culture and Xpert assay were 72.7% (16/22), 27.3% (6/22) and 31.8% (7/22), respectively, the specificity were 78.6% (22/28), 75.0% (21/28) and 96.4% (27/28), respectively, the accuracy were 76.0% (38/50), 54.0% (27/50) and 68.0% (34/50), respectively, and the Yoden index was 0.51, 0.02 and 0.28, respectively. Conclusion: Nanopore sequencing assay of BALF samples may have better diagnostic performance than Xpert and MGIT 960 cultures, and may improve the positive detection rate of BALF in suspected PTB patients. But this method cannot exclude pulmonary tuberculosis.

Key words: Tuberculosis, pulmonary, Bronchoalveolar lavage fluid, Nanotechnology, Molecular diagnostic techniques, Comparative study