Easy tongue swabs could improve TB testing uptake

Millions of tuberculosis (TB) cases go undiagnosed each year, in part because the standard way to test — producing a sputum sample — can be difficult or uncomfortable. To explore whether a simpler method might help reach more people, researchers led by Adithya Cattamanchi asked patients, caregivers and healthcare workers how they felt about using tongue swabs instead of sputum. Between September 2023 and February 2024, teams in Viet Nam and Zambia interviewed 76 people: adults with TB symptoms, caregivers of children being evaluated for TB, and healthcare workers who had collected tongue swabs. The goal was not to measure laboratory accuracy, but to understand whether tongue swabs would be acceptable to real people and practical for health systems. By listening to those who would give, collect and act on test results, the study aimed to identify what would help or hinder wider use of tongue swab testing in routine TB screening.

The research used in-depth interviews and a framework analysis to organize responses about acceptability, usability and feasibility. Interview participants included people presenting with TB symptoms, caregivers of children undergoing TB evaluation, and healthcare workers who collected tongue swabs, for a total of 76 participants. Findings were grouped by themes that influence whether a test would be taken up: ease of use, diagnostic accuracy, diagnostic yield, hygiene, risk of TB transmission during sample collection, time to test result, and trust in healthcare workers and the health system. Across interviews, most participants said they preferred a tongue swab to providing sputum. Many described tongue swabs as comfortable and easy, noting that expectorating sputum can be physically uncomfortable and difficult. Participants generally felt tongue swabs could be suitable for everyone, but emphasized that beliefs about diagnostic accuracy and the likelihood of a correct result would strongly shape their preference.

The study suggests that tongue swab–based testing for TB could be highly acceptable and practical if health systems adopt it. Because many people and health workers described tongue swabs as easier and more hygienic than sputum, introducing tongue swabs into routine screening could make testing less painful and more accessible, particularly for people who struggle to produce sputum. However, acceptability depends on confidence in results: perceived diagnostic accuracy, test yield and speed of results all matter to patients and caregivers. The research highlights the social and operational factors—trust in health workers, concerns about transmission during sampling, time-to-result considerations, and hygiene—that programs must address when introducing a new method. Ultimately, incorporating tongue swabs into TB diagnostic guidelines, alongside clear communication about accuracy and training for clinic staff, would be key steps toward broader implementation and better case finding.