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WHO Gets Behind Rapid Tuberculosis Test

If you're making a newfangled machine to test for a disease that's a worldwide scourge, you can't beat getting the endorsement of the World Health Organization.

Today, WHO said countries around the globe should adopt a fast, accurate method for DNA fingerprinting to determine a person's tuberculosis status while they wait. Last year TB killed 1.7 million people, WHO estimates.

Current practice in many less-developed countries is a test, more than 100 years old, that involves analyzing a sputum sample under a microscope. That can miss TB -- especially in kids and people with HIV. It also doesn't help determine whether the TB is resistant to conventional drug treatment. That takes a separate, more time-consuming culture.

WHO says use of the new test could lead to "a three-fold increase in the diagnosis of patients with drug-resistant TB" and double the diagnosis of TB in people with HIV.

A recently published study in the New England Journal of Medicine showed the automated test, made by company called Cepheid, finds about 98 percent of people with TB and is highly accurate in figuring out which bacteria are resistant to rifampin, a key antibiotic used against TB.

The advance in testing doesn't come cheap. The testing equipment, which can be used for other assays, costs around $64,000 in developed countries. The machine is sold in the United States, but the TB test cartridge for it isn't yet available here.

In poorer countries with big TB problems, Cepheid will sell the machine for about $17,000 and each test will cost a little less than $17. (See more on pricing here.)

Cepheid CEO John Bishop tells Shots developing countries will still need help buying the equipment. Demand will depend on "how the foundations line up to support the acquisition of the system," he says.

Copyright 2020 NPR. To see more, visit https://www.npr.org.

Scott Hensley edits stories about health, biomedical research and pharmaceuticals for NPR's Science desk. During the COVID-19 pandemic, he has led the desk's reporting on the development of vaccines against the coronavirus.