Diagnostic value of tNGS vs Xpert MTB/RIF in childhood TB

Objectives: To evaluate the diagnostic value of targeted next generation sequencing (tNGS) in childhood tuberculosis (TB) and compare the accuracy with Xpert MTB/RIF method. Methods: Children aged <= 18 years with symptoms suggestive of TB during July 2021 to December 2022 at Beijing Children's Hospital were included, and the performances of tNGS and Xpert were evaluated. Results: A total of 103 children with suspected TB were recruited, including 72 discharge diagnosis of TB and 31 non-TB cases. The mean age was 7.37 +/- 4.77 years, and 62.1 % were male. The most common type of specimens was gastric aspirate (GA) (59, 57.3 %). Among all the 72 TB patients, tNGS showed higher sensitivity than Xpert, but the difference was not significant (34.7 %, 25/72 vs 20.8 %, 15/72; P = 0.063). The specificities of tNGS and Xpert were 87.1 % (27/31) and 96.8 % (30/31), respectively (P = 0.162). Among different types of specimen, the highest sensitivity of tNGS on sputum and pus was observed (80.0 %, 4/5), followed by pleural effusion (50.0 %, 2/4). One rifampin resistance and one protionamide resistance were detected in bacteriologically confirmed TB by tNGS. Conclusion: tNGS had a higher sensitivity but lower specificity compared to Xpert in diagnosis of children TB. tNGS yielded higher sensitivity than Xpert on gastric aspirate and sputum and pus.