Use of metagenomic next-generation sequencing for accurate diagnosis of tuberculous pleurisy: a retrospective cohort study.

BACKGROUND: Tuberculous pleurisy (TP) presents persistent diagnostic challenges owing to the suboptimal sensitivity of conventional microbiological assays. This study aimed to evaluate the diagnostic performance of metagenomic next-generation sequencing (mNGS) in diagnosing TP using formalin-fixed paraffin-embedded (FFPE) pleural biopsy tissues.

METHODS: This retrospective study evaluated the diagnostic efficacy of mNGS in FFPE pleural samples of suspected TP patients at The First Affiliated Hospital of Soochow University between April 1, 2018 and February 1, 2023. Those patients with inadequate pleural specimens for mNGS analysis were excluded. Diagnosis of TP was established according to the WS 288-2017 Health Industry Standard of the People's Republic of China.

RESULTS: A total of 73 patients were enrolled in this study and divided into the TP group and non-tuberculous pleurisy (NTP) group. The TP group comprised 51 patients with a median age of 52 years, including 33 (64.7%) males. The NTP group consisted of 22 patients with a median age of 64 years, including 13 (59.1%) males. Our results showed that mNGS assay on FFPE in pleural biopsies had a sensitivity of 78.43% [95% confidence interval (CI): 0.667-0.901] and a specificity of 100% (95% CI: 1.000-1.000) in diagnosing TP. In the 51 TP cases, mNGS detectedcomplex (MTBC) in 40 (78.43%) cases and non-tuberculous mycobacteria (NTM) in 31 (60.78%) cases. Of these, 16 cases were MTBC infections alone and 7 cases were NTM infections alone, while 24 were mixed MTBC and NTM infections.

CONCLUSIONS: mNGS of FFPE of pleural biopsy tissues not only improves the diagnostic efficiency of TP, but also potential accurately distinguishes between MTBC and NTM, providing molecular and microbial basis for the diagnosis of TP, which is helpful for the rapid diagnosis and precise treatment of TP.