Open-source real-time quantitative RT-PCR-based on a RNA standard for the assessment of SARS-CoV-2 viral load
Mem. Inst. Oswaldo Cruz
;
116: e210237, 2021. tab, graf
Article
in English
|
LILACS-Express
| LILACS
| ID: biblio-1356489
ABSTRACT
BACKGROUND Detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) target genes by molecular methods has been chosen as the main approach to identify individuals with Coronavirus disease 2019 (COVID-19) infection. OBJECTIVES In this study, we developed an open-source RNA standard-based real-time quantitative RT-PCR (RT-qPCR) assay for quantitative diagnostics of SARS-CoV-2 from nasopharynx, oropharynx, saliva and plasma samples. METHODS AND FINDINGS We evaluated three SARS-CoV-2 target genes and selected the RNA-dependent RNA polymerase (RdRp) gene, given its better performance. To improve the efficiency of the assay, a primer gradient containing 25 primers forward and reverse concentration combinations was performed. The forward and reverse primer pairs with 400 nM and 500 nM concentrations, respectively, showed the highest sensitivity. The LOD95% was ~60 copies per reaction. From the four biological matrices tested, none of them interfered with the viral load measurement. Comparison with the AllplexTM 2019-nCoV assay (Seegene) demonstrated that our test presents 90% sensitivity and 100% specificity. MAIN CONCLUSIONS We developed an efficient molecular method able to measure absolute SARS-CoV-2 viral load with high replicability, sensitivity and specificity in different clinical samples.
Full text:
Available
Index:
LILACS (Americas)
Type of study:
Prognostic study
Language:
English
Journal:
Mem. Inst. Oswaldo Cruz
Journal subject:
Tropical Medicine
/
Parasitology
Year:
2021
Type:
Article
Affiliation country:
Brazil
/
United States
Institution/Affiliation country:
Hospital Moinhos de Vento/BR
/
Johns Hopkins School of Medicine/US
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