Rapid Point-of-Care Test Detects Tuberculosis from Tongue Swab and Sputum

Diagnosis can be time-consuming, and collecting sputum samples may be difficult for some patients while posing risks of airborne transmission. To overcome these barriers, researchers have developed a rapid point-of-care tuberculosis test designed to provide results during a single clinic visit.

Engineers at Northwestern University developed DASH MTB, a rapid molecular test compatible with the existing DASH (Diagnostic Analyzer for Specific Hybridization) Rapid PCR system. The assay detects Mycobacterium tuberculosis, the bacterium responsible for tuberculosis, using either tongue swabs or sputum samples. Designed for point-of-care testing, the system could expand diagnostic access in remote and underserved areas where conventional laboratory services are limited.

The test uses a cartridge-based workflow that nonlaboratory personnel can perform with minimal training. Samples are prepared in three simple steps before being loaded into the analyzer for automated detection. The cartridges demonstrated storage stability at temperatures up to 45°C (113°F), potentially supporting deployment in settings with limited refrigeration, air conditioning, or reliable electricity.

The study was published on November 12 in Open Forum Infectious Diseases. The work reflects collaborations with the University of Washington, the University of Cape Town, and Stellenbosch University. According to the findings, the rapid test’s performance matched Cepheid’s Xpert MTB/RIF Ultra test, with DASH MTB reaching 100% accuracy for true-negative tests and 91% accuracy for true-positive results.

“Diagnosis is the weakest link in tuberculosis care. Tuberculosis diagnosis can be complex and time-consuming. Bacterial culture is the gold standard. It has high sensitivity, but the time-to-result is lengthy, and it is technically challenging and prone to contamination,” said Sally McFall, research professor of biomedical engineering at Northwestern’s McCormick School of Engineering and codirector of the Center for Innovation in Global Health Technologies.

“Sputum is the preferred specimen for tuberculosis diagnosis, but up to one-third of patients cannot produce sputum and thus cannot be diagnosed. Here, we tested using tongue swab specimens in addition to sputum and showed high sensitivity and specificity with both specimen types using a test that could provide the result within the clinic visit,” said McFall.

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