Browsing by Author "Cattamanchi A"

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Diagnostic Yield of Tongue Swab- Compared to Sputum-Based Molecular Testing for Tuberculosis in Four High-Burden Countries.
(2026-Apr-30) Moe CA; Luswata RK; Barrameda AJ; Le H; Muzazu S; Crowder R; Andama AO; Denkinger CM; Muyoyeta M; Phan H; Cattamanchi A; Yu C
BACKGROUND: Tongue swabs are a promising alternative specimen for tuberculosis (TB) diagnosis. Although test specificity exceeds 98%, sensitivity is lower than sputum-based molecular testing. We investigated whether the use of tongue swabs could increase sample availability, resulting in similar diagnostic yield. METHODS: In this cross-sectional study (July 2024-January 2025), we screened consecutive people with presumptive TB at health centers in the Philippines, Vietnam, Uganda, and Zambia. Participants were asked to provide tongue swabs and referred for routine sputum collection. Tongue swabs were tested in research laboratories using the MiniDock MTB Test (Guangzhou Pluslife Biotech Co., Ltd., China); sputum was tested using WHO-recommended molecular testing per national guidelines. We compared diagnostic yield, defined as proportion of positive test results among all participants, between tongue swab- and sputum-based molecular testing with a prespecified 3.0% non-inferiority margin. RESULTS: Of 1639 participants, 851 (51.9%) were female, 415 (25.3%) were diagnosed with HIV, and 132 (8.1%) were children <5 years. All provided tongue swabs, but only 1389 (84.7%) produced sputum. Diagnostic yield was 3.8% (63/1639) for tongue swabs and 4.1% (68/1639) for sputum-based (68/1639, 4.1%) molecular testing. The difference (0.3%, 95% CI -0.6 to +1.2) was within the prespecified non-inferiority margin. Results were consistent across countries and key subgroups (age, sex, and HIV status). CONCLUSIONS: Tongue swab-based molecular testing with MiniDock MTB achieved non-inferior diagnostic yield compared with sputum-based molecular testing. These findings support scale-up of swab-based platforms as a cost-efficient alternative, particularly where sputum collection is challenging or smear microscopy remains the primary diagnostic method.
Multicountry assessment of tongue swabs for tuberculosis using a common protocol for Xpert MTB/RIF Ultra testing: a prospective diagnostic accuracy study.
(2026-May-14) de Vos M; Le H; Marcelo D; Ajide B; Alí-Francia KG; Borkman AL; Desravines R; Chang HT; Dowling W; Kamulegeya L; Marconi S; Moe CA; Rockman L; Shuma B; Christopher DJ; Hapeela N; Muyoyeta M; Nakiyingi L; Theron G; Ugarte-Gil C; Hung NV; Luong DV; Yu C; Alland D; Denkinger CM; Ellner J; Dorman SE; Kremer K; Manabe YC; Nahid P; Ruhwald M; Shah M; Penn-Nicholson A; Cattamanchi A; Bimba JS
BACKGROUND: Despite advancements in tuberculosis diagnostics, many cases remain unconfirmed because of challenges in conventional sputum-based testing. This study aimed to evaluate the diagnostic accuracy of tongue swab sampling as a non-invasive alternative for tuberculosis diagnosis using Xpert MTB/RIF Ultra (Ultra). METHODS: We conducted a large-scale, multicountry, prospective diagnostic accuracy study of Ultra using tongue swabs in people with presumptive pulmonary tuberculosis. Participants were enrolled consecutively at primary health centres and hospitals across eight countries from June 26, 2023, to Feb 15, 2024, and the study was coordinated by three consortia. Eligible participants were individuals aged 12 years or older or 18 years or older, according to the consortium involved, with presumptive pulmonary tuberculosis or at least one risk factor for tuberculosis and a positive tuberculosis screening test at the select consortia. Standardised tongue swab collection and processing protocols were used in all countries. Sensitivity and specificity with 95% CI values were calculated against sputum liquid or solid culture (primary) and sputum Ultra (secondary) reference standards using Wilson's score method. Fisher's exact tests were used for subgroup comparisons, with p values < 0·05 considered statistically significant. FINDINGS: Among the 1844 participants included in the analysis, 389 tested positive and 1455 tested negative for pulmonary tuberculosis based on the primary sputum culture reference standard. 871 (47·2%) participants were female and 973 (52·7%) were male, with a mean age of 43 years (range 12-90). Among the 1844 participants, 399 (21·7%) were enrolled in Viet Nam, 166 (9·0%) in India, 427 (23·2%) in South Africa, 271 (14·7%) in the Philippines, 138 (7·5%) in Nigeria, 102 (5·5%) in Zambia, 175 (9·5%) in Uganda, and 166 (9·0%) in Peru. Tongue swab Ultra testing showed a sensitivity of 65·6% (95% CI 60·6-70·3) and specificity of 98·5% (95% CI 97·7-99·1) against the culture-based reference standard. Sensitivity estimates varied across collection centres and were higher in individuals without HIV than in those living with HIV (68·4% vs 50·0%; absolute difference 18·4 percentage points [95% CI 3·3-33·4]). When sputum Ultra was used as the reference standard, sensitivity was 75·4% (95% CI 69·0-78·8). Tongue swab Ultra showed higher sensitivity than sputum smear microscopy. Invalid or error result rates were variable and high at certain sites (range 0-16%). INTERPRETATION: Tongue swabs are a promising sample type for rapid diagnostic tests for tuberculosis, with moderate sensitivity and high specificity when Ultra was used as the reference standard. However, further research is needed to optimise protocols for Ultra testing and develop assays tailored to tongue swab specimens. Adoption of tongue swab-based molecular testing could expand tuberculosis diagnostics access, especially for populations unable to produce sputum, thus supporting global tuberculosis elimination goals. FUNDING: National Institute of Allergy and Infectious Diseases, United States Agency for International Development.
Pulmonary Tuberculosis Detection with MiniDock MTB Using Swab Samples.
(2026-Apr-30) Yerlikaya S; Chirwa M; Ajide B; Castro MDM; Ha H; Kato-Maeda M; Kisakye E; Marcelo D; Mochizuki T; Rockman L; Steadman A; Thangakunam B; Bimba JS; Christopher DJ; Muyoyeta M; Phan H; Theron G; Yu C; Kremer K; Phillips PPJ; Nahid P; Denkinger CM; Cattamanchi A; Andama A
BACKGROUND: Improved diagnostic tools for tuberculosis that are suitable for use in peripheral health centers are essential for reducing the persistent gap between estimated and notified cases. The diagnostic accuracy and usability of the MiniDock MTB test for detecting pulmonary tuberculosis is unknown. METHODS: We conducted a prospective, cross-sectional study at outpatient centers in India, Nigeria, the Philippines, South Africa, Uganda, Vietnam, and Zambia. Patients 12 years of age or older with presumptive pulmonary tuberculosis were enrolled between September 12, 2024, and March 31, 2025. Assessment with MiniDock MTB was performed with sputum swabs and tongue swabs. Diagnostic accuracy was evaluated against a sputum-culture-based reference and as compared with sputum-smear microscopy and Xpert MTB/RIF Ultra assay. Usability was assessed with a system usability scale and direct observation. RESULTS: A total of 1380 participants were enrolled; 255 (18.5%) had human immunodeficiency virus infection and 226 (16.4%) had culture-confirmed tuberculosis. MiniDock MTB sensitivity was 85.7% (95% confidence interval [CI], 80.4 to 90.0) with sputum and 79.6% (95% CI, 73.8 to 84.7) with tongue swabs; specificity was greater than 97.5% for both. Results of sputum tests with MiniDock MTB closely matched those with Xpert MTB/RIF Ultra for sensitivity (difference, -2.8 percentage points; 95% CI, -6.0 to 0.5). MiniDock MTB had greater sensitivity than smear microscopy for tests of sputum (difference, 24.3 percentage points; 95% CI, 17.9 to 30.7) and tongue swabs (difference, 18.3 percentage points; 95% CI, 12.0 to 24.7). The test showed diagnostic accuracy that was consistent with World Health Organization (WHO) accuracy targets for near-point-of-care tuberculosis diagnostics (≥85% sensitivity for sputum and ≥75% for nonsputum and ≥98% specificity for both). The median score on the system usability scale (range, 0 to 100, with higher scores indicating better perceived usability) was 75 (interquartile range, 65 to 80), which indicated good usability. No adverse events related to the index test were reported. CONCLUSIONS: MiniDock MTB met WHO targets for diagnostic accuracy and usability for tuberculosis detection across diverse clinical settings. (Funded by the National Institutes of Health and others; Rapid Research in Diagnostics Development for TB Network and Assessing Diagnostics at Point-of-Care for Tuberculosis ClinicalTrials.gov numbers, NCT04923958 and NCT05941052.).
"That is why I trust": a qualitative study on acceptability and feasibility of novel tongue swab diagnostics to assess people presenting with tuberculosis symptoms in Viet Nam and Zambia.
(2026-Jun-19) Sales A; Le H; Muzazu S; Kunda-Ng'andu E; Castro MDM; Kerkhoff AD; Phan H; Denkinger CM; Cattamanchi A; West N; Muyoyeta M
BACKGROUND: Millions of tuberculosis (TB) cases are estimated to be undiagnosed and unreported annually. Sputum has been the primary approach for diagnostic testing, but tongue swabs are being investigated as an alternative to expand testing. To understand potential uptake and implementation, we explored the acceptability, usability, and feasibility of tongue swab-based TB testing from the perspectives of healthcare workers, people undergoing TB screening, and caregivers in Viet Nam and Zambia. METHODS: We interviewed people with symptoms of TB, caregivers of children undergoing TB evaluation, and healthcare workers who collected tongue swabs (n = 76 participants) between September 2023 and February 2024. Interviews were analyzed using framework analysis to elucidate preferences, experiences, and acceptability of tongue swabs vs. sputum. Findings were further organized according to acceptability and feasibility to understand barriers and facilitators to uptake. RESULTS: Most participants preferred tongue swab to sputum collection. The perceived usability and feasibility of tongue swabs were high. Key themes that influenced the acceptability of tongue swabs included 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, many participants described tongue swabs as a comfortable and easy way to test for TB, compared to the physical discomfort and difficulty expectorating sputum. Participants described tongue swabs as suitable for everyone, yet perceived diagnostic accuracy was crucial in shaping test preference. CONCLUSION: Tongue swab-based testing for TB is likely to be highly acceptable and feasible if incorporated into TB diagnostic guidelines. Future integration of tongue swabs in facilities and communities should target drivers of acceptability.
Tongue swab Xpert MTB/RIF Ultra testing for TB using a revised consensus protocol.
(2026-Apr-27) Ajide B; Moe CA; Barrameda J; Chirwa M; Rockman L; de Haas P; de Vos M; Kato-Maeda M; Tasca B; Bimba J; Yu C; Denkinger CM; Kremer K; Nahid P; Cattamanchi A; Theron G; Muyoyeta M
BACKGROUNDTongue swabs are a promising specimen type for TB diagnosis. In a previous study, using a consensus protocol, tongue swabs tested with Xpert MTB/RIF Ultra outperformed sputum smear microscopy, but a substantial proportion (6.1%) of results were non-actionable (e.g., invalid/error). We evaluated a revised protocol for tongue swab Xpert Ultra testing in four high-burden countries.METHODSParticipants aged ≥12 years with presumptive TB were enrolled from outpatient clinics in the Philippines, South Africa, Nigeria, and Zambia. Tongue swabs were processed using Sample Reagent (SR, Cepheid, USA) diluted 2:1 with phosphate buffer or phosphate-buffered saline and tested with Xpert Ultra. Diagnostic performance was assessed against culture-based microbiological reference standard and compared to sputum tests.RESULTSFrom March to November 2024, 1,168 participants were enrolled (median age 37 [IQR: 28-48] years; 46.7% female; 21.8% living with HIV; 18.5% culture-confirmed TB). The proportion of non-actionable tongue swab results was 5.6% overall, but <4% in all countries except South Africa (15.4%). Tongue swab sensitivity was 66.0% (95% CI: 59.0-72.5); specificity was 99.6% (95% CI: 98.9-99.9).CONCLUSIONThe revised protocol yielded low error rates at most sites and moderate sensitivity, supporting tongue swabs as an alternative specimen for Xpert Ultra testing when sputum is unavailable..
Tongue Swab Xpert MTB/RIF Ultra Testing for Tuberculosis Using a Revised Consensus Protocol: A multi-country diagnostic accuracy study.
(2025-Jul-10) Ajide B; Moe CA; Barrameda J; Chirwa M; Rockman L; de Haas P; de Vos M; Kato-Maeda M; Tasca B; Bimba J; Yu C; Denkinger CM; Kremer K; Nahid P; Cattamanchi A; Theron G; Muyoyeta M
BACKGROUND: Tongue swabs are a promising specimen for tuberculosis (TB) diagnosis. In a previous study using a consensus protocol, tongue swabs tested with Xpert MTB/RIF Ultra (Xpert Ultra, Cepheid, USA) outperformed sputum smear microscopy, but a substantial proportion (6.1%) of results were non-actionable (e.g., invalid/error). We evaluated a revised protocol in four high TB burden countries. METHODS: Participants aged ≥12 years with presumptive TB were enrolled from outpatient clinics in the Philippines, South Africa, Nigeria, and Zambia. Tongue swabs were processed using Sample Reagent (SR, Cepheid, USA) diluted 2:1 with phosphate buffer or phosphate-buffered saline and tested with Xpert Ultra. Diagnostic performance was assessed against a culture-based microbiological reference standard and compared to sputum-based tests. RESULTS: From March to November 2024, 1168 participants were enrolled (median age 37 [IQR 28-48] years; 46.7% female, 21.8% living with HIV, 18.5% culture-confirmed TB). The proportion of nonactionable results was 5.6% overall, but was less than 4% in all countries except South Africa (15.4%). Tongue swab sensitivity was 66.0% (95% CI 59.0-72.5); specificity was 99.6% (95% CI 98.9-99.9). CONCLUSION: The revised protocol yielded low error rates at most sites and moderate sensitivity, supporting tongue swabs as an alternative when sputum is unavailable.