WHO introduces tongue swab testing for TB; phlegm not required

This technique will benefit children, senior citizens, asymptomatic individuals, and people living with HIV who struggle to produce phlegm samples for testing.

Researchers have developed a new non-invasive swab testing toolkit for tuberculosis (TB) detection. This new test can be a breakthrough in TB diagnosis, which is otherwise dependent on sputum (phlegm) collection, an unpleasant and difficult experience for many patients. 

The Global Tuberculosis Report 2025 estimates that 1.2 million individuals succumbed to TB globally in 2024. Overall, 10.7 million people fell ill with TB.  

TB is a preventable and curable condition if diagnosed early. Many times, it is misconstrued as a cough due to some food items consumed, like rice, bananas, or guavas, that may cause coughing. Or a fever thought to be caused by weather changes. According to a 2024 study, by the Journal of Family Medicine and Primary Care, 76 per cent of people were misdiagnosed for typhoid, malaria, pneumonia, and other viral infections, without any consideration of TB.

Why does this new test matter?

The swab-based testing toolkit developed by Stop TB in association with the World Health Organisation (WHO) will use a single tongue swab instead of mucus collected from deep inside the lungs.

Analysing a person's phlegm is the oldest test continued to decipher if a person is infected with TB. Often, many health workers find working with sputum, calling it "nasty" and difficult to work with. The new test in comparison is quite simple.

This technique will benefit children, senior citizens, asymptomatic individuals, and people living with HIV who struggle to produce sputum samples for testing. 

A study published in the New England Journal of Medicine establishes that the new device is economical ( less than $180), with each test costing less than $4. According to them, the tests are accurate, rapid, compact, extraction-free, and well-suited for less resourceful settings. 

These tests also have the potential to test for other diseases like HIV, mpox, and HPV infections, making diagnostics more patient-centric and convenient for multiple diagnoses. 

"These new tools could be truly transformative for tuberculosis, by bringing fast, accurate diagnosis closer to people, saving lives, curbing transmission and reducing costs," Dr Tedros Adhanom Ghebreyesus, director-general, WHO, says.

Bridging the accessibility gap

These new tests will allow rapid diagnosis of airborne TB. Therefore, it may reduce delays caused by long-distance travel to central laboratories for testing.

This simple test, similar to a COVID-19 test, can drastically expand TB screening everywhere. Particularly in rural areas where accessibility to laboratories and other high-end medical resources is limited. The easy-to-use test can also be utilised for mass screenings in countries like India, where TB continues to be a major public health concern.