DOI: https://doi.org/10.14710/jbtr.v12i2.30964

Saliva vs Sputum for Xpert MTB/RIF Ultra: A Preliminary Diagnostic Study in Suspected TB

1Department of Community Medicine, State Islamic University Syarif Hidayatullah, Indonesia

2Department of Microbiology, State Islamic University Syarif Hidayatullah, Indonesia

3Department of Microbiology, Persahabatan Hospital, Indonesia

4 Department Pulmonology and Respiratory medicine, Universitas Indonesia, Indonesia

View all affiliations
Received: 11 Jan 2026; Revised: 22 Apr 2026; Accepted: 12 May 2026; Available online: 29 Aug 2026; Published: 31 Aug 2026.
Open Access Copyright (c) 2026 Journal of Biomedicine and Translational Research
Creative Commons License This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.

Citation Format:
Abstract

Background: Tuberculosis (TB) diagnosis is routinely established through sputum-based testing. However, obtaining high-quality sputum samples remains challenging, particularly for molecular diagnostic methods. Saliva has emerged as an attractive alternative specimen because it is safe, non-invasive, and easy to collect.

Objective: This study aimed to evaluate the diagnostic accuracy of Xpert MTB/RIF Ultra in saliva compared with sputum as the reference standard for detecting Mycobacterium tuberculosis (MTB) and rifampicin resistance.

Methods: This preliminary diagnostic accuracy study employed a cross-sectional design and included 22 patients with suspected TB attending a pulmonary outpatient clinic. Each participant underwent parallel Xpert MTB/RIF Ultra testing using paired sputum and saliva samples. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), likelihood ratios, and overall diagnostic accuracy were calculated using 2×2 contingency table analysis, with sputum Xpert MTB/RIF Ultra serving as the reference standard.

Results: The results of this study showed that 22 subjects were included. MTB was detected in sputum samples from 16 subjects and in saliva samples from 13 subjects. Among respondents examined using both specimens, 11 had positive results, and 4 had negative results. Saliva examination produced five false-negative and two false-positive results. The sensitivity was 68.8%, the specificity was 66.7%, the PPV was 84.6%, and the NPV was 44.4%. At low bacterial concentrations, the results of this study were more likely to be unfavourable. The likelihood ratios were LR⁺ 2.06 and LR⁻ 0.47, indicating that sputum examination cannot yet be replaced. However, based on this study’s results, saliva has potential as a screening test, particularly in primary healthcare settings.

Conclusion: Saliva represents a practical alternative specimen in cases where sputum collection is problematic and may support earlier detection of tuberculosis

 

Note: This article has supplementary file(s).

Fulltext View|Download |  Research Instrument
Copyright Transfer Agreement (CTA)
Subject
Type Research Instrument
  Download (301KB)    Indexing metadata
Email colleagues
Keywords: Tuberculosis, Xpert MTB/RIF Ultra, saliva, sputum, diagnostic accuracy
Funding: LP2PM (PUSLITPEN) Syarif Hidayatullah State Islamic University Jakarta

Article Metrics:

Article Info
Section: Original Research Articles
Language : EN
  1. World Health Organization. Global tuberculosis report 2025. 2025
  2. Kementerian Kesehatan Republik Indonesia. PETUNJUK TEKNIS Pemeriksaan Tuberkulosis Menggunakan Tes Cepat Molekuler GeneXpert. 2023;3
  3. Nielsen MC, Clarner P, Paroha R, Lee S, Thwe PM, Ren P. Comparison of Analytical Sensitivity (Limit of Detection) of Xpert MTB/RIF and Xpert MTB/RIF Ultra for Non-Sputum Specimens. Pathogens. 2023;1–9
  4. World Health Organization. WHO consolidated guidelines on tuberculosis. 2021
  5. Kementerian Kesehatan Republik Indonesia. Pedoman Nasional Pelayanan Kedokteran Tata Laksana Tuberkulosis. 2020;
  6. David A, Singh L, Peloakgosi-shikwambani K, Nsingwane Z, Molepo V, Cangelosi G, et al. Diagnostic accuracy of self-collected tongue swabs for Mycobacterium tuberculosis complex detection in individuals being assessed for tuberculosis in South Africa using the Xpert MTB / RIF Ultra assay. Clin Microbiol Infect [Internet]. 2025;31(6):1040–5. Available from: https://doi.org/10.1016/j.cmi.2025.01.029
  7. Mesman AW, Calderon R, Soto M, Coit J, Aliaga J, Mendoza M, et al. Mycobacterium tuberculosis detection from oral swabs with Xpert MTB / RIF ULTRA : a pilot study. BMC Res Notes [Internet]. 2019;10–2. Available from: https://doi.org/10.1186/s13104-019-4385-y
  8. Byanyima P, Kaswabuli S, Musisi E, Nabakiibi C, Zawedde J, Sanyu I, et al. Feasibility and Sensitivity of Saliva GeneXpert MTB / RIF Ultra for Tuberculosis Diagnosis in Adults in Uganda. 2022;(August):1–8
  9. Tang P, Liu R, Qin L, Xu P, Xiong Y, Deng Y, et al. Accuracy of Xpert ® MTB / RIF Ultra test for posterior oropharyngeal saliva for the diagnosis of paucibacillary pulmonary tuberculosis : a prospective multicenter study. 2023;12
  10. Astuti D, Lihawa N, Putrawan HA, Djaharuddin I, Santoso A, Tabri NA. Feasibility and Sensitivity of Genexpert MTB / RIF Ultra on Saliva for Diagnosis of Pulmonary Tuberculosis. 2025;XXVI:6789–99
  11. TB CARE I. International Standards for Tuberculosis Care. 2014;
  12. Icksan AG, Raja M, Napitupulu S, Nawas MA, Nurwidya F. Chest X ‑ ray Findings Comparison between Multi ‑ drug ‑ resistant Tuberculosis and Drug ‑ sensitive Tuberculosis. 2018;42–6
  13. Namuganga AR, Chegou NN, Mubiri P, Walzl G, Mayanja-kizza H. Suitability of saliva for Tuberculosis diagnosis : comparing with serum. 2017;1–11
  14. Naik S, Dhaneja S, Khilari A, Basu S, Shetty A, Rodrigues, et al. Correlation of Trace Detection in Gene Xpert MTB/RIF Ultra with MGIT TB Culture in a High TB-Endemic Country. 2025
  15. Fernández L, Eisenhut M, Ismail N, Korobitsyn A, Se V, Brands A, et al. Xpert MTB/RIF Ultra assay for tuberculosis disease and rifampicin resistance in children (Review). 2025;
  16. Ayalew S, Wegayehu T, Wondale B, Kebede D, Osman M, Niway S, et al. Detection of Mycobacterium tuberculosis complex in saliva by quantitative PCR: A potential alternative specimen for pulmonary tuberculosis diagnosis. 2025;1–14
  17. Zhang F, Wang Y, Zhang X, Liu K. Diagnostic accuracy of oral swab for detection of pulmonary tuberculosis : a systematic review and meta-analysis. 2024;
  18. Wood RC, Luabeya AK, Dragovich RB, Olson AM, Lochner KA, Weigel KM, et al. Diagnostic accuracy of tongue swab testing on two automated tuberculosis diagnostic platforms, Cepheid Xpert MTB / RIF Ultra. 2024;62(4):1–11
  19. Mazzola E, Monte PD, Piersimoni C, Giudice AD, Camaggi A, Pedrotti C et al. Multicenter Evaluation of Xpert MTB/RIF Ultra Tests Reporting Detection of “Trace” of Mycobacterium tuberculosis DNA. 2021;101–3
  20. Dorman SE, Schumacher SG, Alland D, Nabeta P, Armstrong DT, King B, et al. Xpert MTB / RIF Ultra for detection of Mycobacterium tuberculosis and rifampicin resistance : a prospective multicentre diagnostic accuracy study. 2018;18(January)
  21. Id AA, Beci G, Id MG, Id GL, Bisognin F, Id FC, et al. Evaluation of trace calls by Xpert MTB / RIF ultra for clinical management in low TB burden settings. 2022;59:1–13. Available from: http://dx.doi.org/10.1371/journal.pone.0272997
  22. Lounnas M, Bourdin A, Kremer L, Perre P Van De, Godreuil S, Tuaillon E, et al. Detection of Mycobacterium tuberculosis in paucibacillary sputum : performances of the Xpert MTB / RIF ultra compared to the Xpert MTB / RIF , and IS6110 PCR HAL Id : hal-02105943. 2020;
  23. Andama A, Whitman GR, Crowder R, Reza TF, Jaganath D, Mulondo J, et al. Accuracy of Tongue Swab Testing Using Xpert MTB-RIF Ultra for. 2022;
  24. Wang Y, He Y, Wang L, Zhang Y, Wang M. Diagnostic Yield of Nucleic Acid Amplification Tests in Oral Samples for Pulmonary Tuberculosis : A Systematic Review and Meta-analysis. 2023;
  25. Mansfield M, Mclaughlin M, Roycroft E, Montgomery L, Keane J, Rogers TR. Diagnostic Performance of Xpert MTB / RIF Ultra Compared with Predecessor Test , Xpert MTB / RIF , in a Low TB Incidence Setting : a Retrospective Service Evaluation. 2022;
  26. Church EC, Steingart KR, Cangelosi GA, Ruhwald M, Kohli M, Shapiro AE. Oral swabs with a rapid molecular diagnostic test for pulmonary tuberculosis in adults and children: a systematic review E. Lancet Glob Heal [Internet]. 2024;12(1):e45–54. Available from: http://dx.doi.org/10.1016/S2214-109X(23)00469-2
  27. Wang Y, Ma Z, Liu Z, Dong X, Shu W, Wei M, et al. Tongue swab-based molecular diagnostics for pulmonary tuberculosis and drug resistance in adults: A prospective multicenter diagnostic accuracy study. J Infect [Internet]. 2025;91(1):106517. Available from: https://doi.org/10.1016/j.jinf.2025.106517
  28. David J, Jerry S, Adrienne E, Chandler E, Jonah S, Alexander W, et al. Xpert MTB / RIF Ultra assay for pulmonary tuberculosis and rifampicin resistance in adults and adolescents. 2025;
  29. Singh S, Choudhury V, Singh A, Saluja S. Understanding likelihood ratios. 2012;2(4):236–8
  30. Trevethan R. Screening , Sensitivity , Specificity , and So Forth : A Second , Somewhat Skeptical , Sequel. 2019;2(1)

Last update:

No citation recorded.

Last update:

No citation recorded.