Rapid Tongue Swab Molecular Test Detects Pulmonary Tuberculosis at Point of Care

Access to timely diagnosis is limited in many settings by dependence on sputum collection and laboratory infrastructure. Faster, simpler testing could curb delays to treatment and reduce patient attrition. New findings demonstrate a swab-based molecular approach that produces results in under 35 minutes and can be performed by minimally trained users.

Investigators at the Heidelberg Faculty of Medicine at Heidelberg University, working with the University of California, San Francisco (UCSF), evaluated the MiniDock MTB swab-based molecular test for detecting Mycobacterium tuberculosis. The system is designed for use outside centralized laboratories and aims to simplify workflows for frontline services. Results from the study were published in the New England Journal of Medicine.

The method uses two portable devices. One device lyses bacterial cells in a tongue or sputum swab to release genetic material, and the second performs molecular detection of Mycobacterium tuberculosis DNA. Visual signal lights indicate a positive or negative result, and the platform can operate on battery power to support use where reliable electricity is limited.

In a multicenter study of 1,380 individuals with suspected pulmonary tuberculosis recruited at outpatient facilities in India, Nigeria, South Africa, Uganda, Vietnam, Zambia, and the Philippines, participants provided both sputum and tongue swab samples. Diagnostic performance was assessed by sensitivity and specificity for each specimen type, and usability was evaluated under simulated routine conditions with test‑naïve, non‑specialist users following the manufacturer’s instructions. The study team also compared diagnostic yield with existing sputum-based diagnostics.

Tongue swab testing correctly identified approximately 80% of confirmed cases (sensitivity 80%) with a specificity of 99.5%, and showed comparable accuracy when applied to sputum. Overall performance was similar to established laboratory-based molecular assays considered the current gold standard, and diagnostic yield using tongue swabs was comparable to sputum-based approaches. 

The World Health Organization (WHO) has recommended the test as the first near point‑of‑care molecular diagnostic for tuberculosis, and pilot implementation in high‑burden countries is underway. Additional practical advantages cited include compact form factor, rapid turnaround time, minimal training requirements, and considerably lower costs than conventional molecular assays.

"Our study demonstrates that this test meets the World Health Organization's target product profile criteria for near point of care tuberculosis diagnostics," says first author Dr. Seda Yerlikaya. "These findings provide robust evidence to support consideration of the test for use in adolescents and adults presenting with symptoms suggestive of tuberculosis."

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Heidelberg Faculty of Medicine
UCSF School of Medicine