CENTRAL AND EASTERN UGANDA — The World Health Organization last month recommended the MiniDock MTB, a portable tuberculosis test made by the Chinese company Pluslife, following a multi-country study published in the New England Journal of Medicine. The device, announced last year, can analyze either phlegm or a tongue swab to detect DNA from the tuberculosis bacteria.

Tuberculosis is the world's deadliest infectious disease, killing more than a million people a year. The most common test to determine infection has not changed since the late 1800s and relies on phlegm, a sample that some patients, including children, the elderly and those weakened by disease, cannot easily produce. Conventional phlegm-based testing can produce false positives and fails to detect tuberculosis in about half of actual cases.

During the COVID-19 pandemic, swab-based testing advanced with increased funding from researchers and industry, and some companies including Pluslife have since shifted the technology to tuberculosis testing.

The MiniDock MTB processes samples by heating, spinning them down, and machine scanning for the bacteria's DNA. The device costs $300, with a per-test fee of $3 to $4, and is faster than conventional tests. Researchers enrolled almost 1,400 patients with tuberculosis symptoms at health centers across seven countries in Africa and Asia, including Uganda, and found the test easy to use and accurate using either phlegm or tongue swab.

Adithya Cattamanchi, a pulmonologist at UC Irvine, said the conventional test presents a challenge for patients. "It's a nasty substance. No one likes it, right? You don't like to cough it up." He described patients cycling through multiple facilities before receiving a diagnosis. "Many people are making three, four, five visits before they finally come to a health center where there is TB testing available," he said. "And they keep transmitting the disease as they move between these different facilities, which puts others at risk of infection."

"To have this low-cost option is, I think, really going to help countries scale up," Cattamanchi said.

Alfred Andama, a microbiologist at Makerere University College of Health Sciences who worked on the study, said the goal had long been to make diagnosis easier. "So for a long time, we have been trying to make the diagnosis of tuberculosis easier, cheaper, and quicker," Andama said. "Most of the patients who are suspected to have TB could have access to TB testing," he said. He added: "Detecting patients early, starting them on treatment early and following up to make sure they adhere to treatments makes a lot of improvement in their lives."

Lucica Ditiu, executive director of Stop TB Partnership, said "There is a lot of excitement in the world" about the device but noted limitations. "We all think this is an amazing tool with two caveats," Ditiu said. The test cannot distinguish between regular tuberculosis and the drug-resistant variety that does not respond to first-line antibiotics. "For that type of work, we don't think this is the tool yet. Maybe it needs some improvement," she said.

Dr. Robert Koch first identified the rod-shaped bacterium that causes tuberculosis nearly 150 years ago.