Assessment of Direct RT-qPCR for SARS-CoV-2 Detection by Multiplexed Assay

Abstract RNA extraction is usually required for molecular detection methods. On the other hand, this step implies time consumption and additional cost to laboratorial routine. This study evaluated the use of direct-RT-qPCR for SARS-CoV-2 detection compared to the gold standard extraction method. An...

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Main Authors: Rachel Cruz Alves, José Henrique Franscisco Roma, Bruno Moreira Carneiro, Renata Dezengrini Slhessarenko, Juliana Helena Chavez Pavoni
Format: Article
Language:English
Published: Instituto de Tecnologia do Paraná (Tecpar) 2025-05-01
Series:Brazilian Archives of Biology and Technology
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Online Access:http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132025000100306&lng=en&tlng=en
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author Rachel Cruz Alves
José Henrique Franscisco Roma
Bruno Moreira Carneiro
Renata Dezengrini Slhessarenko
Juliana Helena Chavez Pavoni
author_facet Rachel Cruz Alves
José Henrique Franscisco Roma
Bruno Moreira Carneiro
Renata Dezengrini Slhessarenko
Juliana Helena Chavez Pavoni
author_sort Rachel Cruz Alves
collection DOAJ
description Abstract RNA extraction is usually required for molecular detection methods. On the other hand, this step implies time consumption and additional cost to laboratorial routine. This study evaluated the use of direct-RT-qPCR for SARS-CoV-2 detection compared to the gold standard extraction method. An exploratory stage was performed using DMSO, glycerol, Tween 20 and Easy Extract® DNA-RNA addition in a pool of highly positive clinical samples (CT<25), which were subsequently tested by AllplexTM 2019-nCoV assay. Validation was performed with 54 SARS-CoV-2 positive and five negative clinical samples comparing three distinct conditions: (i) 1:1 water dilution, (ii) 1.5% DMSO dilution, or (iii) crude samples. Results of the exploratory stage showed Cycle Threshold (CT) values very close to those obtained by the reference extraction step in high viral load samples. However, when lower viral load samples were analyzed, a slight concordance was observed compared to the extraction step. In the validation stage, it was observed that water or 1.5% DMSO dilution presented 97.3% of concordance in samples with CT≤30, resulting in 97.4% of sensitivity and 0.83 Kappa coefficient. Sensitivity was reduced with samples CT>30 and with crude samples. The methodology showed reproducibility with differents operators. These results reinforce the good performance of direct RT-qPCR methods in active SARS-CoV-2 infection, allowed cost and time reduction of diagnosis.
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spelling doaj-art-009d843dee4a4c7390c3c528fb71e3392025-08-20T02:33:12ZengInstituto de Tecnologia do Paraná (Tecpar)Brazilian Archives of Biology and Technology1678-43242025-05-016810.1590/1678-4324-2025240420Assessment of Direct RT-qPCR for SARS-CoV-2 Detection by Multiplexed AssayRachel Cruz Alveshttps://orcid.org/0000-0002-5258-0292José Henrique Franscisco Romahttps://orcid.org/0000-0001-7990-6750Bruno Moreira Carneirohttps://orcid.org/0000-0002-2355-7907Renata Dezengrini Slhessarenkohttps://orcid.org/0000-0002-3246-899XJuliana Helena Chavez Pavonihttps://orcid.org/0000-0003-2568-9601Abstract RNA extraction is usually required for molecular detection methods. On the other hand, this step implies time consumption and additional cost to laboratorial routine. This study evaluated the use of direct-RT-qPCR for SARS-CoV-2 detection compared to the gold standard extraction method. An exploratory stage was performed using DMSO, glycerol, Tween 20 and Easy Extract® DNA-RNA addition in a pool of highly positive clinical samples (CT<25), which were subsequently tested by AllplexTM 2019-nCoV assay. Validation was performed with 54 SARS-CoV-2 positive and five negative clinical samples comparing three distinct conditions: (i) 1:1 water dilution, (ii) 1.5% DMSO dilution, or (iii) crude samples. Results of the exploratory stage showed Cycle Threshold (CT) values very close to those obtained by the reference extraction step in high viral load samples. However, when lower viral load samples were analyzed, a slight concordance was observed compared to the extraction step. In the validation stage, it was observed that water or 1.5% DMSO dilution presented 97.3% of concordance in samples with CT≤30, resulting in 97.4% of sensitivity and 0.83 Kappa coefficient. Sensitivity was reduced with samples CT>30 and with crude samples. The methodology showed reproducibility with differents operators. These results reinforce the good performance of direct RT-qPCR methods in active SARS-CoV-2 infection, allowed cost and time reduction of diagnosis.http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132025000100306&lng=en&tlng=enCOVID-19 Nucleic Acid TestingSARS-CoV-2Molecular DiagnosisSensitivity and Specificity.
spellingShingle Rachel Cruz Alves
José Henrique Franscisco Roma
Bruno Moreira Carneiro
Renata Dezengrini Slhessarenko
Juliana Helena Chavez Pavoni
Assessment of Direct RT-qPCR for SARS-CoV-2 Detection by Multiplexed Assay
Brazilian Archives of Biology and Technology
COVID-19 Nucleic Acid Testing
SARS-CoV-2
Molecular Diagnosis
Sensitivity and Specificity.
title Assessment of Direct RT-qPCR for SARS-CoV-2 Detection by Multiplexed Assay
title_full Assessment of Direct RT-qPCR for SARS-CoV-2 Detection by Multiplexed Assay
title_fullStr Assessment of Direct RT-qPCR for SARS-CoV-2 Detection by Multiplexed Assay
title_full_unstemmed Assessment of Direct RT-qPCR for SARS-CoV-2 Detection by Multiplexed Assay
title_short Assessment of Direct RT-qPCR for SARS-CoV-2 Detection by Multiplexed Assay
title_sort assessment of direct rt qpcr for sars cov 2 detection by multiplexed assay
topic COVID-19 Nucleic Acid Testing
SARS-CoV-2
Molecular Diagnosis
Sensitivity and Specificity.
url http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132025000100306&lng=en&tlng=en
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