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]. 2023 Oct 11:2023.10.10.23296833.
doi: 10.1101/2023.10.10.23296833.

Tongue swab testing on two automated tuberculosis diagnostic platforms, Cepheid Xpert® MTB/RIF Ultra and Molbio Truenat® MTB Ultima

Rachel C Wood  1 , Angelique K Luabeya  2 , Rane B Dragovich  1 , Alaina M Olson  1 , Katherine A Lochner  1 , Kris M Weigel  1 , Renée Codsi  1 , Humphrey Mulenga  2 , Margaretha de Vos  3 , Mikashmi Kohli  3 , Adam Penn-Nicholson  3 , Mark Hatherill  2 , Gerard A Cangelosi  1
Affiliations

Tongue swab testing on two automated tuberculosis diagnostic platforms, Cepheid Xpert® MTB/RIF Ultra and Molbio Truenat® MTB Ultima

Rachel C Wood et al. medRxiv. .

Update in

Abstract

Tongue dorsum swabbing is a potential alternative to sputum collection for tuberculosis (TB) testing. Previous studies showed that Cepheid Xpert® MTB/RIF Ultra (Xpert Ultra) can detect Mycobacterium tuberculosis (MTB) DNA in tongue swabs stored in buffer, with 72% sensitivity and 100% specificity relative to a sputum microbiological reference standard (sputum MRS). The present study evaluated a more convenient sample collection protocol (dry swab storage), combined with streamlined sample processing protocols, for side-by-side analysis using two commercial TB diagnostic tests: Xpert Ultra and Molbio Truenat® MTB Ultima (MTB Ultima). Copan FLOQSwabs were self-collected, or collected by study workers, from 321 participants in Western Cape, South Africa. All participants had symptoms suggestive of TB, and 245 of them had sputum MRS-confirmed TB (by sputum culture and/or Xpert Ultra). One tongue swab per participant was tested on Xpert Ultra and another tongue swab was tested with MTB Ultima. Xpert Ultra was 75.4% sensitive and 100% specific, and MTB Ultima was 71.6% sensitive and 96.9% specific, relative to sputum MRS. When sample lysates that were false-negative by MTB Ultima were frozen, thawed, and re-tested, MTB Ultima sensitivity rose to 79.1%. Both tests were more sensitive with swabs from participants with higher sputum Xpert semi-quantitative results. The protocol for Xpert Ultra enabled fast and easy testing of dry-stored swabs with no loss of accuracy relative to previous methods. MTB Ultima testing of dry-stored swabs exhibited comparable performance to Xpert Ultra. These results further support tongue swabs as easy-to-collect samples for high-throughput TB testing.

PubMed Disclaimer

References

    1. World Health Organization. 2022. Global Tuberculosis Report 2022
    1. Pai M, Dewan PK, Swaminathan S. 2023. Transforming tuberculosis diagnosis. Nat Microbiol 8:756–759. - PubMed
    1. Branigan D. 2022. 2022 Tuberculosis Diagnostics Pipeline Report. Treatment Action Group, New York, NY
    1. Reid M, Agbassi YJP, Arinaminpathy N, Bercasio A, Bhargava A, Bhargava M, Bloom A, Cattamanchi A, Chaisson R, Chin D, Churchyard G, Cox H, Denkinger CM, Ditiu L, Dowdy D, Dybul M, Fauci A, Fedaku E, Gidado M, Harrington M, Hauser J, Heitkamp P, Herbert N, Herna Sari A, Hopewell P, Kendall E, Khan A, Kim A, Koek I, Kondratyuk S, Krishnan N, Ku C-C, Lessem E, McConnell EV, Nahid P, Oliver M, Pai M, Raviglione M, Ryckman T, Schäferhoff M, Silva S, Small P, Stallworthy G, Temesgen Z, van Weezenbeek K, Vassall A, Velásquez GE, Venkatesan N, Yamey G, Zimmerman A, et al. Scientific advances and the end of tuberculosis: a report from the Lancet Commission on Tuberculosis. The Lancet doi: 10.1016/S0140-6736(23)01379-X. - DOI - PubMed
    1. LaCourse SM, Seko E, Wood R, Bundi W, Ouma GS, Agaya J, Richardson BA, John-Stewart G, Wandiga S, Cangelosi GA. 2022. Diagnostic performance of oral swabs for non-sputum based TB diagnosis in a TB/HIV endemic setting. PLoS One 17:e0262123. - PMC - PubMed

Publication types