Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
[Preprint]. 2025 Mar 18:rs.3.rs-6225530.
doi: 10.21203/rs.3.rs-6225530/v1.

Oral washes and tongue swabs for Xpert MTB/RIF Ultra-based tuberculosis diagnosis in people with and without the ability to make sputum

Loren Rockman  1 , Shima Abdulgader  1 , Stephanie Minnies  1 , Zaida Palmer  1 , Charissa C Naidoo  1 , Daphne Naidoo  1 , Rouxjeane Venter  1 , Gcobisa Ndlangalavu  1 , Byron W P Reeve  1 , Andrew M Marino  2 , Tim J Bull  3 , Alaina M Olson  4 , Rachel Wood  4 , Gerard A Cangelosi  4 , Robin M Warren  1 , Grant Theron  1
Affiliations

Oral washes and tongue swabs for Xpert MTB/RIF Ultra-based tuberculosis diagnosis in people with and without the ability to make sputum

Loren Rockman et al. Res Sq. .

Update in

Abstract

Background: Oral samples show promise for tuberculosis (TB) diagnosis. Data from different samples and people with sputum scarce TB are limited.

Methods: We assessed Xpert MTB/RIF Ultra (Ultra) in symptomatic people at clinics (Cohort A, n=891) or at antiretroviral therapy (ART)-initiation without syndromic preselection (Cohort B, n=258). In Cohort A, we collected oral washes (OWs) and, separately, tongue swabs (flocked, foam with heat). In Cohort B, we collected OWs, three flocked tongue swabs (comparing one with heat to two pooled swabs) and, separately, buccal swabs, periodontal brushes. We offered sputum induction and did different culture methods on a subset of Cohort B tongue swabs.

Results: In Cohort A, Ultra on OWs, flocked tongue and foam swabs had sensitivities of 80% (95% confidence interval 56, 94), 59% (53, 65) and 65% (58, 72) and high specificities. In Cohort B, OWs and single heated swabs had 71% (42, 92) and 64% (35, 87) sensitivity, respectively. Pooled tongue swabs, buccal swabs and periodontal brushes had low sensitivities. MGIT960 had the highest sensitivity [64% (35, 87)] of culture methods. Oral sampling detected TB in sputum-scarce people [Cohort A: 25% (7/28) flocked and foam swab-positive; Cohort B: 18% (10/56) OW-, 23% (13/56) single flocked swab-positive]. In Cohort B, this would at least double the people with a positive Ultra result (sputum or oral) if induction were unavailable.

Conclusion: Ultra on OWs or foam tongue swabs has higher sensitivity than other oral-based approaches and detects sputum-scarce TB, resulted in more people diagnosed compared to Ultra on expectorated sputum.

Keywords: Xpert MTB/RIF Ultra; oral washes; tongue swabs; tuberculosis.

PubMed Disclaimer

Conflict of interest statement

Additional Declarations: The authors declare no competing interests.

Figures

Figure 1
Figure 1
Flow chart showing enrolment, specimen collection and processing, and tests in Cohorts A and B.
Figure 2
Figure 2
Forest plot of Ultra sensitivity and specificity on different oral samples in Cohort A, overall and stratified by HIV. Oral washes, foam swabs, and flocked swabs has the highest sensitivity.
Figure 3
Figure 3
Forest plot of Ultra and culture sensitivity and specificity on oral samples in Cohort B. OWs had the highest sensitivity of oral samples.
Figure 4
Figure 4
Number of people with a positive result in Cohorts A and B. In both cohorts, more people were detected exclusively by OW Ultra than any other test. Each oral sampling method also detected people missed by other approaches. The first column includes people with an OW, whereas the second includes people with tongue swabs (in Cohort B, OWs and tongue swabs were in the same people but are disaggregated here for clarity).
See this image and copyright information in PMC

References

    1. World Health Organization. Global Tuberculosis Report 2023. World Health Organization, Geneva, Switzerland. 2023.
    1. World Health Organization. Target product profile for tuberculosis diagnosis and detection of drug resistance. World Health Organization, Geneva, Switzerland. 2024.
    1. Nathavitharana RR, Garcia-Basteiro AL, Ruhwald M, Cobelens F, Theron G. Reimagining the status quo: How close are we to rapid sputum-free tuberculosis diagnostics for all? EBioMedicine. 2022;78. - PMC - PubMed
    1. Abdulgader SM, Okunola AO, Ndlangalavu G, Reeve BW, Allwood BW, Koegelenberg CF, et al. Diagnosing tuberculosis: what do new technologies allow us to (not) do? Respiration. 2022;101(9):797–813. - PMC - PubMed
    1. 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 and Molbio Truenat MTB Ultima. Journal of Clinical Microbiology. 2024;62(4):e00019–24. - PMC - PubMed

Publication types

LinkOut - more resources