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Pooling samples to increase testing capacity with Xpert Xpress SARS-CoV-2 during the Covid-19 pandemic in Lao People’s Democratic Republic

The COVID-19 pandemic created the need for large-scale testing of populations. However, most laboratories do not have sufficient testing capacity for mass screening. We evaluated pooled testing of samples, as a strategy to increase testing capacity in Lao PDR. Samples of consecutive patients were te...

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Autores principales: Iem, Vibol, Xangsayarath, Phonepadith, Chittamany, Phonenaly, Suthepmany, Sakhone, Siphanthong, Souvimone, Paboriboune, Phimpha, Somphavong, Silaphet, Konstantina, Kontogianni, Khan, Jahangir A. M., Edwards, Thomas, Wingfield, Tom, Creswell, Jacob, Dominguez, Jose, Cuevas, Luis E.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9522287/
https://www.ncbi.nlm.nih.gov/pubmed/36173954
http://dx.doi.org/10.1371/journal.pone.0275294
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author Iem, Vibol
Xangsayarath, Phonepadith
Chittamany, Phonenaly
Suthepmany, Sakhone
Siphanthong, Souvimone
Paboriboune, Phimpha
Somphavong, Silaphet
Konstantina, Kontogianni
Khan, Jahangir A. M.
Edwards, Thomas
Wingfield, Tom
Creswell, Jacob
Dominguez, Jose
Cuevas, Luis E.
author_facet Iem, Vibol
Xangsayarath, Phonepadith
Chittamany, Phonenaly
Suthepmany, Sakhone
Siphanthong, Souvimone
Paboriboune, Phimpha
Somphavong, Silaphet
Konstantina, Kontogianni
Khan, Jahangir A. M.
Edwards, Thomas
Wingfield, Tom
Creswell, Jacob
Dominguez, Jose
Cuevas, Luis E.
author_sort Iem, Vibol
collection PubMed
description The COVID-19 pandemic created the need for large-scale testing of populations. However, most laboratories do not have sufficient testing capacity for mass screening. We evaluated pooled testing of samples, as a strategy to increase testing capacity in Lao PDR. Samples of consecutive patients were tested in pools of four using the Xpert Xpress SARS CoV-2 assay. Positive pools were confirmed by individual testing, and we describe the performance of the test and savings achieved. We also diluted selected positive samples to describe its effect on the assays CT values. 1,568 patients were tested in 392 pools of four. 361 (92.1%) pools were negative and 31 (7.9%) positive. 29/31 (93.5% (95%CI 77–99%) positive pools were confirmed by individual testing of the samples but, in 2/31 (6.5%) the four individual samples were negative, suggesting contamination. Pools with only one positive sample had higher CT values (lower RNA concentrations) than the respective individual samples, indicating a dilution effect, which suggested an increased risk of false negative results with dilutions >1:10. However, this risk may be low if the prevalence of infection is high, when pools are more likely to contain more than one positive sample. Pooling saved 67% of cartridges and substantially increased testing capacity. Pooling samples increased SARS-CoV-2 testing capacity and resulted in considerable cartridge savings. Given the need for high-volume testing, countries may consider implementation of pooling for SARS-CoV-2 screening.
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spelling pubmed-95222872022-09-30 Pooling samples to increase testing capacity with Xpert Xpress SARS-CoV-2 during the Covid-19 pandemic in Lao People’s Democratic Republic Iem, Vibol Xangsayarath, Phonepadith Chittamany, Phonenaly Suthepmany, Sakhone Siphanthong, Souvimone Paboriboune, Phimpha Somphavong, Silaphet Konstantina, Kontogianni Khan, Jahangir A. M. Edwards, Thomas Wingfield, Tom Creswell, Jacob Dominguez, Jose Cuevas, Luis E. PLoS One Research Article The COVID-19 pandemic created the need for large-scale testing of populations. However, most laboratories do not have sufficient testing capacity for mass screening. We evaluated pooled testing of samples, as a strategy to increase testing capacity in Lao PDR. Samples of consecutive patients were tested in pools of four using the Xpert Xpress SARS CoV-2 assay. Positive pools were confirmed by individual testing, and we describe the performance of the test and savings achieved. We also diluted selected positive samples to describe its effect on the assays CT values. 1,568 patients were tested in 392 pools of four. 361 (92.1%) pools were negative and 31 (7.9%) positive. 29/31 (93.5% (95%CI 77–99%) positive pools were confirmed by individual testing of the samples but, in 2/31 (6.5%) the four individual samples were negative, suggesting contamination. Pools with only one positive sample had higher CT values (lower RNA concentrations) than the respective individual samples, indicating a dilution effect, which suggested an increased risk of false negative results with dilutions >1:10. However, this risk may be low if the prevalence of infection is high, when pools are more likely to contain more than one positive sample. Pooling saved 67% of cartridges and substantially increased testing capacity. Pooling samples increased SARS-CoV-2 testing capacity and resulted in considerable cartridge savings. Given the need for high-volume testing, countries may consider implementation of pooling for SARS-CoV-2 screening. Public Library of Science 2022-09-29 /pmc/articles/PMC9522287/ /pubmed/36173954 http://dx.doi.org/10.1371/journal.pone.0275294 Text en © 2022 Iem et al https://creativecommons.org/licenses/by/4.0/This is an open access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
spellingShingle Research Article
Iem, Vibol
Xangsayarath, Phonepadith
Chittamany, Phonenaly
Suthepmany, Sakhone
Siphanthong, Souvimone
Paboriboune, Phimpha
Somphavong, Silaphet
Konstantina, Kontogianni
Khan, Jahangir A. M.
Edwards, Thomas
Wingfield, Tom
Creswell, Jacob
Dominguez, Jose
Cuevas, Luis E.
Pooling samples to increase testing capacity with Xpert Xpress SARS-CoV-2 during the Covid-19 pandemic in Lao People’s Democratic Republic
title Pooling samples to increase testing capacity with Xpert Xpress SARS-CoV-2 during the Covid-19 pandemic in Lao People’s Democratic Republic
title_full Pooling samples to increase testing capacity with Xpert Xpress SARS-CoV-2 during the Covid-19 pandemic in Lao People’s Democratic Republic
title_fullStr Pooling samples to increase testing capacity with Xpert Xpress SARS-CoV-2 during the Covid-19 pandemic in Lao People’s Democratic Republic
title_full_unstemmed Pooling samples to increase testing capacity with Xpert Xpress SARS-CoV-2 during the Covid-19 pandemic in Lao People’s Democratic Republic
title_short Pooling samples to increase testing capacity with Xpert Xpress SARS-CoV-2 during the Covid-19 pandemic in Lao People’s Democratic Republic
title_sort pooling samples to increase testing capacity with xpert xpress sars-cov-2 during the covid-19 pandemic in lao people’s democratic republic
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9522287/
https://www.ncbi.nlm.nih.gov/pubmed/36173954
http://dx.doi.org/10.1371/journal.pone.0275294
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