Rapid and Sensitive Diagnosis of Tuberculosis with a Gene-based Microfluidic Platform

<b>Background:</b> Rapid, sensitive diagnosis of tuberculosis (TB) is crucial for effective management. The Xpert MTB/RIF assay is widely used, but its sensitivity is low for paucibacillary TB. We developed a novel rapid pathogen enrichment approach that uses simple and label-free pathogen enrichment via homobifunctional imidoesters using a microfluidic (SLIM) platform and conventional PCR to detect pulmonary TB. <b>Methods:</b> Patients with clinically suspected pulmonary TB were prospectively enrolled from January 2018 to January 2019. Expectorated sputum samples were processed with Xpert and SLIM assays. The SLIM assays were performed twice using 1 ml and 2 ml of sputum. TB cases were defined as patients who were treated with anti-TB chemotherapy for at least 6 months based on clinical features and conventional laboratory results including the Xpert assay. <b>Results:</b> A total of 152 patients with a mean age of 59.6 years were enrolled, and 60 (39%) patients were ultimately diagnosed with TB. Sensitivity of both SLIM assays were greater than that of Xpert; sensitivity of Xpert, SLIM 1 ml and SLIM 2 ml for TB were 37%, 60% (P = 0.001), and 84% (P &lt; 0.001). Specificity of Xpert, SLIM 1 ml, and SLIM 2 ml were 100%, 91%, and 87%, respectively. The difference in sensitivity was most prominent in culture-negative TB, 4% with Xpert, 43% with SLIM 1 ml (P = 0.004), and 76% with SLIM 2 ml (P &lt; 0.001). <b>Conclusion:</b> The SLIM assay improved sensitivity for TB, especially for culture-negative cases. <b>Method:</b> This study was supported by grants from Asan Institute for Life Sciences (2020-7043), Seoul, Korea.