Centralized molecular testing of community-collected tongue swabs for tuberculosis screening among household contacts: a cross-sectional diagnostic performance, yield, and implementation study

The study evaluated the use of tongue swabs instead of sputum samples for tuberculosis detection among 909 household contacts of individuals treated for pulmonary tuberculosis in South Africa. Tongue swabs were collected at home and tested centrally using qPCR method. The sensitivity of tongue swabs was 60.9% and specificity 95.2% compared to sputum samples. Implementation of tongue swab testing increased tuberculosis detection from 1.8% when testing only symptomatic individuals to 5.9% when testing all individuals, representing an 86.2% increase. During implementation, specimen loss was only 2.3% and valid results were obtained in 93.8% of participants. Tongue swabs represent a scalable strategy to expand tuberculosis screening without dependence on sputum samples.