The test - called Xpert MTB/RIF Ultra – uses molecular analysis to detect the genetic markers of Mycobacterium tuberculosis, the bacterium that causes TB, in the saliva of people suspected of infection.

It is the first such test to receive “prequalification” status from the UN health agency, meaning that it has passed stringent quality checks and can now be purchased by governments and UN agencies, as part of their TB eradication efforts.

“This first prequalification of a diagnostic test for tuberculosis marks a critical milestone,” said Dr Yukiko Nakatani, WHO Assistant Director-General for Access to Medicines and Health Products. “It underscores the importance of such groundbreaking diagnostic tools in addressing one of the world's deadliest infectious diseases.”

Fast results

Accurate results can be expected “within hours”, WHO said, adding that at the same time as the test is running, the technology can also identify genetic mutations in the saliva of sufferers that are associated with resistance to first-line TB drugs such as rifampicin. This result will help doctors offer patients alternative, “second-line” treatments, such as bedaquiline and fluoroquinolones – although they are more expensive.

“It is intended for patients who screen positive for pulmonary tuberculosis and who have either not started anti-tuberculosis treatment or received less than three days of therapy in the past six months,” the UN health agency said.

Tuberculosis is one of the world’s leading infectious disease killers, causing over a million deaths annually. The preventable disease is a chronic burden for sufferers who live mainly in low and middle-income countries. Accurate and early detection of TB, especially drug-resistant strains, remains a critical and challenging global health priority, WHO insisted.

“High-quality diagnostic tests are the cornerstone of effective TB care and prevention,” said Dr Rogerio Gaspar, WHO Director for Regulation and Prequalification. “Prequalification paves the way for equitable access to cutting-edge technologies, empowering countries to address the dual burden of TB and drug-resistant TB.”

WHO is currently assessing seven additional TB tests in an effort to expand access to quality-assured testing technology for the disease.

WHO’s assessment for prequalification is based on information submitted by the manufacturer, Cepheid Inc and a review by Singapore’s Health Sciences Authority.