Practical considerations to establish a validated platform for pooled detection of SARS-CoV-2 by droplet digital PCR.

Detection of SARS-CoV-2 has created an enormous workload for laboratories worldwide resulting in a restriction at the time of massive testing. Pool testing is a strategy that reduces time and costs. However, beyond the detection of infectious diseases in blood banks, this approach is rarely implemen...

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Main Authors: Sofía Heckel, Antonella Pacini, Franco Paredes, Ma Victoria Petreli, Marilina Perez, Natalia Adriani, Guadalupe Ibarra, Hugo Menzella, Alejandro Colaneri, Juliana Sesma
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2022-01-01
Series:PLoS ONE
Online Access:https://doi.org/10.1371/journal.pone.0271860
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author Sofía Heckel
Antonella Pacini
Franco Paredes
Ma Victoria Petreli
Marilina Perez
Natalia Adriani
Guadalupe Ibarra
Hugo Menzella
Alejandro Colaneri
Juliana Sesma
author_facet Sofía Heckel
Antonella Pacini
Franco Paredes
Ma Victoria Petreli
Marilina Perez
Natalia Adriani
Guadalupe Ibarra
Hugo Menzella
Alejandro Colaneri
Juliana Sesma
author_sort Sofía Heckel
collection DOAJ
description Detection of SARS-CoV-2 has created an enormous workload for laboratories worldwide resulting in a restriction at the time of massive testing. Pool testing is a strategy that reduces time and costs. However, beyond the detection of infectious diseases in blood banks, this approach is rarely implemented in routine laboratories. Therefore, what was learned from the SARS-CoV-2 pool testing should represent an opportunity to increase diagnostic capabilities. The present work, carried out in the context of a diagnostic laboratory of a public hospital during the COVID-19 pandemic, represents a contribution to this end. The main limitation of pool testing is the risk of false negatives that could have been identified by individual tests. These limitations are the dilution of samples with a low virus load during pooling and that the integrity of the sample may be affected by the quality of the sample collection. Fortunately, both limitations coincide with the main strengths of droplet digital PCR (ddPCR). ddPCR is a third-generation PCR that splits the amplification into thousands of droplets that work in parallel, increasing sensitivity and resistance to inhibitors. Therefore, ddPCR is particularly useful for pool testing. Here we show how to factor between test sensitivity and savings in test time and resources. We have identified and optimized critical parameters for pool testing. The present study, which analyzed 1000 nasopharyngeal samples, showed that the pool testing could detect even a single positive sample with a CT value of up to 30 in pools of 34 samples. This test was performed using three different standard extraction methods, the simplest being heating only, which resulted in substantial savings of extraction reagents in addition to PCR reagents. Moreover, we show that pooling can be extended to use saliva, which is less invasive and allows self-collection, reducing the risk for health personnel.
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spelling doaj.art-db22efcc99c94c4192a96c2c70d8c3512022-12-22T04:38:49ZengPublic Library of Science (PLoS)PLoS ONE1932-62032022-01-011711e027186010.1371/journal.pone.0271860Practical considerations to establish a validated platform for pooled detection of SARS-CoV-2 by droplet digital PCR.Sofía HeckelAntonella PaciniFranco ParedesMa Victoria PetreliMarilina PerezNatalia AdrianiGuadalupe IbarraHugo MenzellaAlejandro ColaneriJuliana SesmaDetection of SARS-CoV-2 has created an enormous workload for laboratories worldwide resulting in a restriction at the time of massive testing. Pool testing is a strategy that reduces time and costs. However, beyond the detection of infectious diseases in blood banks, this approach is rarely implemented in routine laboratories. Therefore, what was learned from the SARS-CoV-2 pool testing should represent an opportunity to increase diagnostic capabilities. The present work, carried out in the context of a diagnostic laboratory of a public hospital during the COVID-19 pandemic, represents a contribution to this end. The main limitation of pool testing is the risk of false negatives that could have been identified by individual tests. These limitations are the dilution of samples with a low virus load during pooling and that the integrity of the sample may be affected by the quality of the sample collection. Fortunately, both limitations coincide with the main strengths of droplet digital PCR (ddPCR). ddPCR is a third-generation PCR that splits the amplification into thousands of droplets that work in parallel, increasing sensitivity and resistance to inhibitors. Therefore, ddPCR is particularly useful for pool testing. Here we show how to factor between test sensitivity and savings in test time and resources. We have identified and optimized critical parameters for pool testing. The present study, which analyzed 1000 nasopharyngeal samples, showed that the pool testing could detect even a single positive sample with a CT value of up to 30 in pools of 34 samples. This test was performed using three different standard extraction methods, the simplest being heating only, which resulted in substantial savings of extraction reagents in addition to PCR reagents. Moreover, we show that pooling can be extended to use saliva, which is less invasive and allows self-collection, reducing the risk for health personnel.https://doi.org/10.1371/journal.pone.0271860
spellingShingle Sofía Heckel
Antonella Pacini
Franco Paredes
Ma Victoria Petreli
Marilina Perez
Natalia Adriani
Guadalupe Ibarra
Hugo Menzella
Alejandro Colaneri
Juliana Sesma
Practical considerations to establish a validated platform for pooled detection of SARS-CoV-2 by droplet digital PCR.
PLoS ONE
title Practical considerations to establish a validated platform for pooled detection of SARS-CoV-2 by droplet digital PCR.
title_full Practical considerations to establish a validated platform for pooled detection of SARS-CoV-2 by droplet digital PCR.
title_fullStr Practical considerations to establish a validated platform for pooled detection of SARS-CoV-2 by droplet digital PCR.
title_full_unstemmed Practical considerations to establish a validated platform for pooled detection of SARS-CoV-2 by droplet digital PCR.
title_short Practical considerations to establish a validated platform for pooled detection of SARS-CoV-2 by droplet digital PCR.
title_sort practical considerations to establish a validated platform for pooled detection of sars cov 2 by droplet digital pcr
url https://doi.org/10.1371/journal.pone.0271860
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