Handheld Device Deliver Low-Cost TB Results in Less Than One Hour

Tuberculosis (TB) remains the deadliest infectious disease globally, affecting an estimated 10 million people annually. In 2021, about 4.2 million TB cases went undiagnosed or unreported, mainly due to the high cost and limitations of testing in regions with a heavy disease burden. The World Health Organization reports that over 1 million children contract TB each year, with more than half of these cases going undiagnosed or unreported. Current TB testing methods involve large, expensive devices that either require on-site technology or the transportation of samples to distant laboratories. The recent resurgence of TB, worsened by disruptions in healthcare systems, highlights the urgent need for accessible and effective diagnostic tools. Researchers have now developed a first-of-its-kind handheld diagnostic device capable of providing quick and accurate TB diagnoses in under an hour.

Developed by researchers at Tulane University (New Orleans, LA, USA), this smartphone-sized, battery-powered lab-in-tube assay (LIT) is a cost-effective solution that enhances TB diagnosis, particularly in rural areas with limited access to healthcare facilities and lab equipment. Over 90% of new TB cases are reported in low- and middle-income countries, making this point-of-care device crucial for such regions. This is the first device capable of detecting Mycobacterium tuberculosis (Mtb) DNA in saliva, along with blood and sputum samples. The ability to use saliva, a more easily obtained sample, for accurate TB diagnosis is especially important for testing children. The LIT test provides a low-cost solution, with each device priced under USD 800 and costing less than USD 3 per test. In contrast, traditional TB diagnostic devices can cost at least USD 19,000, with test prices reaching around USD 100 in some countries.

Image: The lab-in-tube assay could improve TB diagnoses in rural or resource-limited areas (Photo courtesy of Kenny Lass/Tulane University)

In a study published in Science Translational Medicine, the LIT device demonstrated high accuracy when testing blood samples from children in the Dominican Republic. It outperformed the more expensive alternative, with 81% sensitivity compared to 68%, and met the World Health Organization's criteria for TB diagnostics. Blood serum testing, which involves analyzing the liquid portion of blood after coagulation, is particularly essential for children and HIV-positive patients who may have difficulty producing sputum. The results from the LIT assay indicate that blood samples could also be used to track TB treatment progress, as the results closely correspond to improvements in patient symptoms.

“This system reduces the expertise and equipment required for TB diagnosis which is essential for point-of-care application,” said lead author, Brady Youngquist, a graduate student in the Tulane University Center for Cellular and Molecular Diagnostics. “Saliva-based testing for TB is particularly exciting because it can be easily obtained in all patients and can be used for portable testing without the need for blood draw. And sputum is often not produced in children and patients living with HIV, a common co-infection.”