Rapid and Convenient Quantitative Analysis of SARS-CoV-2 RNA in Serous Saliva with a Direct PCR Method
Clinical Examination Group, Center for Precision Medicine Supports, Shimadzu Techno-Research, Inc., 7 Nishinokyo-Shimoaicho, Nakagyo-ku, Kyoto 604-8436, Japan
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Author to whom correspondence should be addressed.
†
Present address: EditForce Inc. West Zone 5#430, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan.
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Present address: Kyoto University Hospital, 54 Shogoin-Kawahara-cho, Sakyo-ku, Kyoto 606-8507, Japan.
Academic Editor: Alberto Arnedo-Pena
Epidemiologia 2021, 2(3), 305-314; https://doi.org/10.3390/epidemiologia2030023
Received: 28 May 2021
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Revised: 5 July 2021
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Accepted: 16 July 2021
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Published: 28 July 2021
(This article belongs to the Special Issue Evolving COVID-19 Epidemiology and Dynamics)
Sensitive and accurate detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), frequently performed using direct polymerase chain reaction (PCR), is essential for restricting the spread of coronavirus disease 2019 (COVID-19). However, studies evaluating accurate detection are still required. This study evaluated the quantitativeness and sensitivity of the Ampdirect™ 2019-nCoV detection kit, a direct PCR method. Using saliva with or without Tris-buffered saline (TBS) dilution, linearity, and limits of the N1 and N2 regions of SARS-CoV-2 genomic RNA were assessed using EDX SARS-CoV-2 RNA standard dissolved in RNase-free water (RFW). Fluorescence intensities in non-diluted saliva were higher than those in TBS-diluted samples. Linear regression analysis of detected quantification cycle values and spiked standard RNA concentrations showed that the coefficient of determination of the N1 and N2 genes was 0.972 and 0.615 in RFW and 0.947 and 0.660 in saliva, respectively. N1- and N2-positive detection rates in saliva were 46% (6/13 tests) and 0% (0/12 tests) at one copy/reaction, respectively. These results indicate good quantitativeness and sensitivity for N1 but not for N2. Therefore, our findings reveal that the Ampdirect™ 2019-nCoV system, especially targeting the N1 gene, enables rapid and convenient quantification of SARS-CoV-2 RNA in saliva at one copy/reaction.
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Keywords:
SARS-CoV-2; COVID-19; PCR; quantitative analysis; serous saliva; Rayleigh scattering influence
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MDPI and ACS Style
Deura, C.; Nakayama, K. Rapid and Convenient Quantitative Analysis of SARS-CoV-2 RNA in Serous Saliva with a Direct PCR Method. Epidemiologia 2021, 2, 305-314. https://doi.org/10.3390/epidemiologia2030023
AMA Style
Deura C, Nakayama K. Rapid and Convenient Quantitative Analysis of SARS-CoV-2 RNA in Serous Saliva with a Direct PCR Method. Epidemiologia. 2021; 2(3):305-314. https://doi.org/10.3390/epidemiologia2030023
Chicago/Turabian StyleDeura, Chikaya, and Kenji Nakayama. 2021. "Rapid and Convenient Quantitative Analysis of SARS-CoV-2 RNA in Serous Saliva with a Direct PCR Method" Epidemiologia 2, no. 3: 305-314. https://doi.org/10.3390/epidemiologia2030023
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