Analytical and clinical performance evaluation of the STANDARD™ M10 MTB/NTM assay for the simultaneous detection of Mycobacterium tuberculosis and nontuberculous mycobacteria

Abstract

The global surge in nontuberculous mycobacteria (NTM) infections, which clinically mimic Mycobacterium tuberculosis (MTB) infections, underscores the need for rapid differential diagnosis. This study evaluated the analytical and clinical performance of the STANDARD™ M10 MTB/NTM assay, a fully automated, cartridge-based, sample-to-result real-time PCR system. Analytical performance was assessed using contrived artificial sputum samples to evaluate inclusivity (3 MTB-complex, 12 NTM species), cross-reactivity (65 respiratory pathogens), and interference (33 substances). The limit of detection (LoD) was compared with two commercial assays, the AdvanSure™ TB/NTM Real-time PCR and the Anyplex™ MTB/NTMe Real-time Detection, using three MTB-complex strains (M. tuberculosis H37Rv, M. bovis, and M. bovis BCG Pasteur) and 15 NTM species. Clinical validation was performed using 70 clinical sputum specimens against both comparators. The STANDARD™ M10 MTB/NTM demonstrated excellent inclusivity and high specificity, with no cross-reactivity or analytical interference (△Ct ≤ 2.0). In the LoD comparison, the STANDARD™ M10 MTB/NTM achieved a lower LoD for MTB H37Rv (10¹ CFU/mL) and major NTM species (M. avium, M. intracellulare, M. abscessus subsp. abscessus) than the comparators, demonstrating superior analytical sensitivity. Moreover, the STANDARD™ M10 MTB/NTM successfully detected M. xenopi, M. scrofulaceum, and M. malmoense, which were missed by alternative assays. In clinical evaluation, it demonstrated 100% overall agreement (95% confidence interval (CI), 94.8–100.0) with the AdvanSure™ TB/NTM Real-time PCR and Anyplex™ MTB/NTMe Real-time Detection assays across a Ct range of 27.41–33.17. The STANDARD™ M10 MTB/NTM assay offers exceptional analytical sensitivity, broad coverage, and, in the absence of an independent reference standard, complete agreement with two established laboratory-based platforms. By incorporating a fully automated workflow and minimizing turnaround time, this system serves as a reliable tool for rapid MTB/NTM differentiation in point-of-care settings.