Diagnostic accuracy of a novel point-of-care tongue swab assay for pulmonary tuberculosis: a multicentre prospective study.

OBJECTIVES: Tuberculosis (TB) remains a leading cause of infectious disease deaths, with underdiagnosis driving ongoing transmission. We evaluated the diagnostic performance of the MiniDock MTB Test (MiniDock), an innovative point-of-care testing molecular system, using tongue swab and sputum specimens.

METHODS: This prospective multicentre study enrolled 594 participants with suspected symptomatic pulmonary TB across seven TB hospitals in Guangdong Province. Tongue swabs and sputum samples were tested using MiniDock system of Pluslife. Sputum specimens were evaluated with Xpert MTB/RIF (Xpert), smear microscopy, and mycobacteria growth indicator tube culture. The diagnostic performance of MiniDock was compared with that of mycobacteria growth indicator tube culture and sputum Xpert findings. Diagnostic performance was compared against a composite microbiological reference standard (MRS).

RESULTS: The sputum MiniDock demonstrated sensitivity and specificity of 98.2% (95% CI, 95.7-99.2%) and 90.4% (95% CI, 86.7-93.2%), compared with sputum Xpert, and 94.2% (95% CI, 90.9-96.6%) and 93.7% (95% CI, 90.3-96.1%) compared with the MRS. The MiniDock test with tongue swabs had a sensitivity of 80.0% (95% CI, 74.8-84.3%) and a specificity of 95.4% (95% CI, 92.5-97.2%) compared with sputum Xpert, and 74.5% (95% CI, 69.1-79.4%) and 96.0% (95% CI, 93.1-97.9%) compared with the MRS. The sensitivity of tongue swab MiniDock varied by bacterial load, ranging from 98.2% (95% CI, 90.2-99.7%) in high-load samples to 47.8% (95% CI, 29.2-67.0%) in very-low-load samples; for sputum samples, the corresponding sensitivities were 100% (95% CI, 93.4-100.0%) and 87.0% (95% CI, 67.9-95.5%), respectively.

CONCLUSIONS: The MiniDock test using tongue swabs and sputum provides a rapid, reliable, and noninvasive point-of-care testing diagnostic option for TB. Although the tongue swab MiniDock has lower sensitivity, its high acceptability makes it a valuable supplementary tool for individuals unable to produce sputum.