People Prefer Tongue Swabs Over Sputum for TB Testing

Tuberculosis (TB) diagnosis often relies on sputum, which can be hard to produce for children, people living with HIV, and others who struggle to produce sputum. Those difficulties create real barriers to timely testing and diagnosis. Tongue swab-based molecular testing has emerged as a promising, non-invasive alternative that could make it easier for many people to be tested, but there has been limited person-centered research on whether patients themselves would accept this approach. To address that gap, Nora West and colleagues carried out a pragmatic survey at primary care facilities in eight countries to learn which sample people prefer. The study enrolled people with presumptive TB and asked them to try both collection methods. After providing both a tongue swab and a sputum sample, participants completed a brief 5-10 minute survey about which method they preferred. The research focused on real-world acceptability among people seeking care, gathering direct feedback from the patients who would be offered these tests in routine settings.

The survey was conducted from October 2023 to July 2024 across eight countries: Vietnam, Philippines, South Africa, Nigeria, Zambia, India, Uganda, and Peru. A total of 1,297 participants were enrolled; the median age was 43 years, 45% were female, and 13% were HIV-positive. Every participant provided both a tongue swab and a sputum sample before completing the short survey about their collection preferences. Overall, 61% (95% CI: 58-64%) of participants preferred tongue swab collection, 22% (95% CI: 20-25%) preferred sputum collection, and 17% (95% CI: 15-19%) reported no preference. Preference for the tongue swab was consistent across different demographic and clinical subgroups. There was some variation by country: preference for tongue swab ranged from 47% in South Africa to 74% in Zambia and Nigeria, showing that while the tongue swab was favored overall, local differences exist.

The clear preference for tongue swab collection has important implications for how TB testing could be offered. Because tongue swabs are non-invasive and easier to collect than sputum, they have the potential to lower barriers to testing for people who cannot produce sputum easily, such as some children and people living with HIV. Patient preference is a key part of making health services more accessible and acceptable, and these findings suggest that adopting tongue swab-based molecular testing could improve the experience of people being evaluated for TB. The consistency of preference across diverse groups and countries strengthens the case for further work to integrate this diagnostic option into care pathways. While acceptability alone does not replace the need to evaluate diagnostic accuracy and implementation logistics, knowing that patients prefer tongue swabs supports the value of continuing research and planning for real-world use of this diagnostic innovation.