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

Bibliographic Data

ID19594394
AuthorsVibol Iem (0000-0001-6155-1402, Liverpool School of Tropical Medicine), Phonenaly Chittamany, Sakhone Suthepmany, Souvimone Siphanthong, Silaphet Somphavong (0000-0002-0773-1493, Centre d’Infectiologie Christophe Mérieux of Laos), Konstantina Kontogianni (0000-0002-5353-3682, Liverpool School of Tropical Medicine), James Dodd (0000-0001-9313-3176, Liverpool School of Tropical Medicine), Jahangir Akber Mahmud Khan (University of Gothenburg), Jose Dominguez (0000-0001-7888-0309, Universitat Autonòma de Barcelona), Tom Wingfield (0000-0001-8433-6887, Liverpool School of Tropical Medicine), Jacob Creswell (0000-0002-4885-940X), Luís E Cuevas (0000-0002-6581-0587, Liverpool School of Tropical Medicine, corresponding author)
EditorsMiguel Ángel García-Bereguiain (0000-0003-0025-3609)
Year2022
Volume2
Issue4
Pagese0000116
Publication date2022-04-04
Peer ReviewedYes
Open AccessYes
TypeARTICLE
VenuePLOS Global Public Health (JOURNAL)
Journal identifiersISSN: 2767-3375 • E-ISSN: 2767-3375
PublisherPublic Library of Science (PLoS) (PUBLISHER)
DOI10.1371/journal.pgph.0000116
PMID36962200
OpenAlexW4225966415
LanguageEN
Citations received1
References cited16

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

Disease · Pandemic · Pathology · Pooling · Sputum · Tuberculosis · COVID-19 diagnosis using AI · Medicine · SARS-CoV-2 detection and testing · Tuberculosis Research and Epidemiology · Internal Medicine · Virology