A promising device offers hope for tuberculosis diagnosis in the "missing millions"

In a recent cutting-edge study, scientists test a diagnostic device using dielectrophoresis that holds promise for improving TB detection and treatment of patients in high-endemic, under-resourced areas. 

The investigators describe a prototype microfluidic lab-on-a-chip system called CAPTURE-XT® from QuantuMDx that can process solubilized sputum from suspected TB patients, capture Mtb bacilli for visual analysis (as a substitute for smear microscopy), and provide a purified sample for molecular confirmation by quantitative PCR (qPCR) and ultimately for genotypic drug-susceptibility analysis. CAPTURE-XT® technology relies on the principle of dielectrophoresis – a little-utilized technique that can be tuned to selectively attract or repel specific particles or cells based on their dielectric properties. In this case, it is the Mtb bacteria that cause TB that are specifically captured and concentrated, while the other sputum contents are washed away.

After optimization using a panel of 50 characterized sputum samples, the performance of the prototype was assessed by a blinded screening of 100 characterized and bio-banked sputum samples provided by the Foundation for Innovative New Diagnostics (FIND).

Concordance with culture diagnosis was 100% for smear-negative samples and 87% for smear-positive samples. Of the smear-positive samples, the high burden sample concordance was 100%.

Reference: “A Novel Microfluidic Dielectrophoresis Technology to Enable Rapid Diagnosis of Mycobacteria Tuberculosis in Clinical Samples,” by Catherine M. Moore, Jasvir Dhillon, Rebecca Flynn, Krzysztof Gizynski, Candice Adams, George Morgan, David McGurk, Eduardo Boada, Shireen Shabestary, Jonathan Peat, Jonathan O’Halloran, Neil G. Stoker, Philip D. Butcher, and Heather Murton (https://doi.org/10.1016/j.jmoldx.2023.04.005). It appears in The Journal of Molecular Diagnostics