Pooling sputum for Xpert MTB/RIF and Xpert Ultra testing during the Covid-19 pandemic in Lao People’s Democratic Republic



Iem, Vibol, Chittamany, Phonenaly, Suthepmany, Sakhone, Siphanthong, Souvimone, Somphavong, Silaphet, Kontogianni, Konstantina, Dodd, James, Khan, Jahangir Akber Mahmud, Dominguez, Jose, Wingfield, Tom ORCID: 0000-0001-8433-6887
et al (show 2 more authors) (2022) Pooling sputum for Xpert MTB/RIF and Xpert Ultra testing during the Covid-19 pandemic in Lao People’s Democratic Republic. PLOS Global Public Health, 2 (4). e0000116-e0000116.

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Abstract

<jats:p>The global Covid-19 pandemic has limited access to molecular TB diagnostics and National Programmes are struggling to maintain essential services. The pooling method (testing several samples together) could reduce the number of cartridges and staff time needed for TB diagnosis but has not been tested within the pandemic. We conducted two independent cross-sectional surveys. Pools composed of four sputum samples were tested using either Xpert-MTB/RIF or Xpert-Ultra. Pooled and individual results were compared to determine the level of agreement. Each survey included 840 participants and 210 pools. In the Xpert MTB/RIF survey, 77/81 (sensitivity 95.1%, 95%CI 87.8%-98.6%) pools containing ≥1 positive sample tested MTB-positive and 4/81 (4.9%, 95%CI 1.4%-12.2%) tested MTB-negative. All 129/129 pools containing MTB-negative samples tested MTB-negative (specificity 100%, 95%CI 97.2%-100%), with 98.1% agreement (Kappa: 0.959). In the Xpert-Ultra survey, 70/70 (sensitivity 100%, 95%CI 94.9%-100%) pools containing ≥ 1 MTB-positive sample tested MTB-positive and 140/140 (specificity 100%, 95%CI 97.4%-100%) pools containing only MTB-negative samples tested MTB-negative, with 100% agreement (Kappa: 1). Pooled testing with Xpert-MTB/RIF and Xpert-Ultra saved 38.3% and 41.7% (322/840 and 350/840, respectively) in cartridge costs alone. The pooling method with Xpert-MTB/RIF and Xpert-Ultra has similar performance to individual testing and can reduce the number of cartridges needed. These efficiencies can facilitate maintenance of stocks and sustain essential services as countries face difficulties for laboratory procurement during the pandemic and will provide cost and time savings post-pandemic.</jats:p>

Item Type: Article
Uncontrolled Keywords: Infectious Diseases, Emerging Infectious Diseases, HIV/AIDS, Clinical Research, 3 Good Health and Well Being
Divisions: Faculty of Health and Life Sciences
Faculty of Health and Life Sciences > Institute of Infection, Veterinary and Ecological Sciences
Depositing User: Symplectic Admin
Date Deposited: 11 May 2022 09:50
Last Modified: 17 Mar 2024 13:43
DOI: 10.1371/journal.pgph.0000116
Open Access URL: https://doi.org/10.1371/journal.pgph.0000116
Related URLs:
URI: https://livrepository.liverpool.ac.uk/id/eprint/3154611