scholarly journals One-step RNA extraction for RT-qPCR detection of 2019-nCoV

2020 ◽  
Author(s):  
Monica Sentmanat ◽  
Evguenia Kouranova ◽  
Xiaoxia Cui
Keyword(s):  
Real Time ◽  
Rna Extraction ◽  
Virus Transmission ◽  
Extraction Methods ◽  
Viral Rna ◽  
Taqman Probe ◽  
N Gene ◽  
Structural Protein ◽  
Diagnostic Panel ◽  
Primer Sets

ABSTRACTThe global outbreak of coronavirus disease 2019 (COVID-19) has placed an unprecedented burden on healthcare systems as the virus spread from the initial 27 reported cases in the city of Wuhan, China to a global pandemic in under three month[1]. Resources essential to monitoring virus transmission have been challenged with a demand for expanded surveillance. The CDC 2019-nCoV Real-Time Diagnostic Panel uses a real-time reverse transcription polymerase chain reaction (RT-PCR) consisting of two TaqMan probe and primer sets specific for the 2019-nCoV N gene, which codes for the nucleocapsid structural protein that encapsulates viral RNA, for the qualitative detection of 2019-nCoV viral RNA in respiratory samples. To isolate RNA from respiratory samples, the CDC lists RNA extraction kits from four manufacturers. In anticipation of a limited supply chain of RNA extraction kits and the need for test scalability, we sought to identify alternative RNA extraction methods. Here we show that direct lysis of respiratory samples can be used in place of RNA extraction kits to run the CDC 2019-nCoV Real-Time Diagnostic assay with the additional benefits of higher throughput, lower cost, faster turnaround and possibly higher sensitivity and improved safety.

scholarly journals Direct Viral RNA Detection of SARS-CoV-2 and DENV in Inactivated Samples by Real-Time RT-qPCR: Implications for Diagnosis in Resource Limited Settings with Flavivirus Co-Circulation

Pathogens ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1558
Author(s):  
Zhan Qiu Mao ◽  
Mizuki Fukuta ◽  
Jean Claude Balingit ◽  
Thi Thanh Ngan Nguyen ◽  
Co Thach Nguyen ◽  
...  
Keyword(s):  
Real Time ◽  
Early Stage ◽  
Rna Extraction ◽  
Viral Rna ◽  
Clinical Samples ◽  
Heat Inactivation ◽  
Resource Limited Settings ◽  
Rna Detection ◽  
Resource Limited ◽  
Starting Point

The RT-qPCR method remains the gold standard and first-line diagnostic method for the detection of SARS-CoV-2 and flaviviruses, especially in the early stage of viral infection. Rapid and accurate viral detection is a starting point in the containment of the COVID-19 pandemic and flavivirus outbreaks. However, the shortage of diagnostic reagents and supplies, especially in resource-limited countries that experience co-circulation of SARS-CoV-2 and flaviviruses, are limitations that may result in lesser availability of RT-qPCR-based diagnostic tests. In this study, the utility of RNA-free extraction methods was assessed for the direct detection of SARS-CoV-2 and DENV-2 in heat-inactivated or chemical-inactivated samples. The findings demonstrate that direct real-time RT-qPCR is a feasible option in comparison to conventional real-time RT-qPCR based on viral genome extraction-based methods. The utility of heat-inactivation and direct real-time RT-qPCR for SARS-CoV-2, DENV-2 viral RNA detection was demonstrated by using clinical samples of SARS-CoV-2 and DENV-2 and spiked cell culture samples of SARS-CoV-2 and DENV-2. This study provides a simple alternative workflow for flavivirus and SARS-CoV-2 detection that includes heat inactivation and viral RNA extraction-free protocols, with aims to reduce the risk of exposure during processing of SARS-CoV-2 biological specimens and to overcome the supply-chain bottleneck, particularly in resource limited settings with flavivirus co-circulation.

scholarly journals SARS-CoV-2 RNA Extraction Using Magnetic Beads for Rapid Large-Scale Testing by RT-qPCR and RT-LAMP

Viruses ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 863 ◽  
Author(s):  
Steffen Klein ◽  
Thorsten G. Müller ◽  
Dina Khalid ◽  
Vera Sonntag-Buck ◽  
Anke-Mareil Heuser ◽  
...  
Keyword(s):  
Reverse Transcription ◽  
Large Scale ◽  
Rna Extraction ◽  
Magnetic Bead ◽  
Viral Rna ◽  
Detection Sensitivity ◽  
Detection Methods ◽  
N Gene ◽  
Extraction Protocol ◽  
Large Scale Testing

Rapid large-scale testing is essential for controlling the ongoing pandemic of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The standard diagnostic pipeline for testing SARS-CoV-2 presence in patients with an ongoing infection is predominantly based on pharyngeal swabs, from which the viral RNA is extracted using commercial kits, followed by reverse transcription and quantitative PCR detection. As a result of the large demand for testing, commercial RNA extraction kits may be limited and, alternatively, non-commercial protocols are needed. Here, we provide a magnetic bead RNA extraction protocol that is predominantly based on in-house made reagents and is performed in 96-well plates supporting large-scale testing. Magnetic bead RNA extraction was benchmarked against the commercial QIAcube extraction platform. Comparable viral RNA detection sensitivity and specificity were obtained by fluorescent and colorimetric reverse transcription loop-mediated isothermal amplification (RT-LAMP) using a primer set targeting the N gene, as well as RT-qPCR using a primer set targeting the E gene, showing that the RNA extraction protocol presented here can be combined with a variety of detection methods at high throughput. Importantly, the presented diagnostic workflow can be quickly set up in a laboratory without access to an automated pipetting robot.

scholarly journals Comparison of Six RNA Extraction Methods for the Detection of Classical Swine Fever Virus by Real-Time and Conventional Reverse Transcription–PCR

2005 ◽  
Vol 17 (6) ◽  
pp. 574-578 ◽  
Author(s):  
Ming Y. Deng ◽  
He Wang ◽  
Gordon B. Ward ◽  
Tammy R. Beckham ◽  
Thomas S. McKenna
Keyword(s):  
Real Time ◽  
Classical Swine Fever Virus ◽  
Rna Extraction ◽  
Classical Swine Fever ◽  
Extraction Methods ◽  
Rt Pcr ◽  
Total Rna ◽  
Reverse Transcription Pcr ◽  
Rna Extraction Methods ◽  
Positive Results

Six RNA extraction methods, i.e., RNAqueous kit, Micro-to-midi total RNA purification system, NucleoSpin RNA II, GenElute mammalian total RNA kit, RNeasy mini kit, and TRIzol LS reagent, were evaluated on blood and 7 tissues from pig infected with classical swine fever virus (CSFV). Each of the 6 extraction methods yielded sufficient RNA for positive results in a real-time reverse transcription–PCR (RT-PCR) for CSFV, and all RNA, except the one extracted from blood by TRIzol LS reagent, yielded positive results in both a conventional RT-PCR for CSFV and a conventional RT-PCR for an endogenous gene encoding β-actin. The RNA extracted from blood by TRIzol LS reagent became positive in both conventional RT-PCR assays when it was diluted to 1:2, 1:4, or up to 1:64 in nuclease-free water. It is concluded that all 6 methods are more or less useful for the detection of CSFV by real-time and conventional RT-PCR in swine blood and tissues. However, some of the 6 reagents offer certain advantages not common to all 6 extraction procedures. For example, RNA extracted by the TRIzol LS reagent constantly had the highest yield; that by the RNAqueous kit had the highest A260/A280 ratio for almost all samples; and that by the NucleoSpin RNA II and the GenElute mammalian total RNA kit was most likely to be free of contaminations with genomic DNA.

scholarly journals Comparison and Sensitivity Evaluation of Three Different Commercial Real-Time Quantitative PCR Kits for SARS-CoV-2 Detection

Viruses ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1321
Author(s):  
Ana Banko ◽  
Gordana Petrovic ◽  
Danijela Miljanovic ◽  
Ana Loncar ◽  
Marija Vukcevic ◽  
...  
Keyword(s):  
Real Time ◽  
Positive Association ◽  
N Gene ◽  
Nucleic Acid Detection ◽  
Real Time Quantitative Pcr ◽  
Sensitivity Evaluation ◽  
Strong Positive Association ◽  
Primer Sets ◽  
Analytical Sensitivities

Real-time reverse transcription polymerase chain reaction (RT-qPCR) is the most sensitive and specific assay and, therefore, is the “gold standard” diagnostic method for the diagnosis of SARS-CoV-2 infection. The aim of this study was to compare and analyze the detection performance of three different commercially available SARS-CoV-2 nucleic acid detection kits: Sansure Biotech, GeneFinderTM, and TaqPathTM on 354 randomly selected samples from hospitalized COVID-19 patients. All PCR reactions were performed using the same RNA isolates and one real-time PCR machine. The final result of the three evaluated kits was not statistically different (p = 0.107), and also had a strong positive association and high Cohen’s κ coefficient. In contrast, the average Ct values that refer to the ORF1ab and N gene amplification were significantly different (p < 0.001 and p < 0.001, respectively), with the lowest obtained by the TaqPathTM for the ORF1ab and by the Sansure Biotech for the N gene. The results show a high similarity in the analytical sensitivities for SARS-CoV-2 detection, which indicates that the diagnostic accuracy of the three assays is comparable. However, the SanSure Biotech kit showed a bit better diagnostic performance. Our findings suggest that the imperative for improvement should address the determination of cut-off Ct values and rapid modification of the primer sets along with the appearance of new variants.

scholarly journals Saliva molecular testing bypassing RNA extraction is suitable for monitoring and diagnosing SARS-CoV-2 infection in children

2021 ◽  
Author(s):  
Marta Alenquer ◽  
Tiago Milheiro Silva ◽  
Onome Akpogheneta ◽  
Filipe Ferreira ◽  
Silvia Vale-Costa ◽  
...  
Keyword(s):  
Rna Extraction ◽  
Extraction Methods ◽  
Cross Sectional Study ◽  
Viral Rna ◽  
Molecular Testing ◽  
Cross Sectional ◽  
The Mean ◽  
Rna Extraction Methods ◽  
Sensitivity Specificity ◽  
Rna Levels

IMPORTANCE Adults are being vaccinated against SARS-CoV-2 worldwide, but the longitudinal protection of these vaccines is uncertain, given the ongoing appearance of SARS-CoV-2 variants. Children are susceptible to infection, and some studies reported that they actively transmit the virus even when asymptomatic, thus affecting the community. Methods to easily test infected children and track the virus they carry are in demand. OBJECTIVE To determine if saliva is an effective sample for detecting SARS-CoV-2 RNA and antibodies in children aged 10 years and under, and associate viral RNA levels to infectivity. DESIGN, SETTING, AND PARTICIPANTS In this cross-sectional study, saliva SARS-CoV-2 RT-qPCR tests, with and without RNA extraction, were validated in 49 hospitalized adults. The test was then applied to 85 children, aged 10 years and under, admitted to the hospital regardless of COVID-19 symptomatology. Amongst 85 children, 29 (63.0%) presented at least one COVID-19 symptom, 46 (54.1%) were positive for SARS-CoV-2 infection, 28 (32.9%) were under the age of 1 and the mean (SD) age was 3.8 (3.4) years. Saliva samples were collected up to 48 h after a positive test by nasopharyngeal (NP) swab-RT-qPCR. EXPOSURE Infection by SARS-COV-2 in adults up to 8 days post-symptom onset. Children admitted to hospital for any reason and therefore with unclear onset of SARS-CoV-2 infection. MAIN OUTCOMES AND MEASURES Saliva RT-qPCR up to CT<37 accurately identifies SARS-CoV-2 infected children, with viral infectivity in tissue culture restricted to CT<26. RESULTS In adults, the accuracy of the saliva SARS-CoV-2 RT-qPCR test was 98.0% (95% confidence intervals [CI]: 89.3%-100%) as compared to NP-RT-qPCR. In children, the sensitivity, specificity, and accuracy of saliva-RT-qPCR tests compared to NP swab-RT-qPCR were, respectively, 84.8% (71.8%-92.4%), 100% (91.0%-100%), and 91.8% (84.0%-96.6%) with RNA extraction and 81.8% (68.0%-90.5%), 100% (91.0%-100%), and 90.4% (82.1%-95.0%) without RNA extraction. The threshold for rescuing infectious particles from saliva was CT<26. There were significant IgM positive responses to the spike protein and its receptor-binding domain (RBD) among children positive for SARS-CoV-2 by NP swab and negative by saliva compared to other groups, indicating late infection onset (>7-10 days). CONCLUSIONS AND RELEVANCE Saliva-molecular testing is suitable in children aged 10 years and under, including infants aged <1 year, even bypassing RNA extraction methods. Importantly, the detected viral RNA levels were significantly above the infectivity threshold in several samples. Further investigation is required to understand how SARS-CoV-2 RNA levels correlate with viral transmission.

scholarly journals Evaluation of the efficacy of LAMP-based SARS-CoV-2 detection with simple RNA extraction from nasopharyngeal swabs: A prospective observational study

PLoS ONE ◽  
2021 ◽  
Vol 16 (12) ◽  
pp. e0260732
Author(s):  
Masaki Karino ◽  
Mizuki Harada ◽  
Chihiro Yamada ◽  
Kyoko Fukuoka ◽  
Megumi Sugo ◽  
...  
Keyword(s):  
Extraction Method ◽  
Prospective Observational Study ◽  
Medical Center ◽  
Rna Extraction ◽  
Extraction Methods ◽  
Viral Rna ◽  
Nasopharyngeal Swab ◽  
Measurement Principle ◽  
Comparison Of The Results ◽  
Reliable Testing

The Loopamp SARS-CoV-2 Detection Kit is used for the detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Loop-mediated isothermal amplification (LAMP) is based on a measurement principle that can be used with a relatively simple device. Detection using this kit requires viral RNA extraction from samples with the QIAGEN QIAamp Viral Mini Kit (QIAGEN extraction) or the Loopamp Viral RNA Extraction Kit (Eiken extraction), which are recommended by the manufacturer. However, the efficacy of LAMP-based SARS-CoV-2 detection using these extraction methods has not been compared. In this study, we aimed to compare the results of genome extraction and detection from nasopharyngeal swab samples using the QIAGEN and Eiken extraction kits. The present study involved patients who presented to the Rinku General Medical Center with suspected COVID-19 (25 positive and 26 negative cases). A comparison of the results obtained using each extraction method with those obtained via PCR showed that the positive, negative, and overall concordance rates between QIAGEN extraction and PCR were 96.0% (24/25 samples), 100% (26/26), and 98.0% (50/51; κ = 0.96, 95% CI = 0.69–1.00), respectively. Results with Eiken extraction were also favorable, with positive, negative, and overall concordance rates of 88.0% (22/25), 100% (26/26), and 94.1% (48/51; κ = 0.88, 95% CI = 0.61–1.00), respectively. Favorable results were obtained using both QIAGEN and Eiken extraction kits. Since Eiken extraction can be completed in a few minutes, it enables prompt and reliable testing for SARS-CoV-2 detection.

scholarly journals Resilient SARS-CoV-2 diagnostics workflows including viral heat inactivation

2020 ◽  
Author(s):  
Maria Jose Lista ◽  
Robert Page ◽  
Helin Sertkaya ◽  
Pedro M. Matos ◽  
Elena Ortiz-Zapater ◽  
...  
Keyword(s):  
Rna Extraction ◽  
Extraction Methods ◽  
N Gene ◽  
Clinical Samples ◽  
Heat Inactivation ◽  
Nucleic Acid Detection ◽  
Minimal Impact ◽  
One Step ◽  
Rna Extraction Methods ◽  
Probe Set

AbstractThere is a worldwide shortage of reagents to perform detection of SARS-CoV-2. Many clinical diagnostic laboratories rely on commercial platforms that provide integrated end-to-end solutions. While this provides established robust pipelines, there is a clear bottleneck in the supply of reagents given the current situation of extraordinary high demand. Some laboratories resort to implementing kit-free handling procedures, but many other small laboratories will not have the capacity to develop those and/or will perform manual handling of their samples. In order to provide multiple workflows for SARS-CoV-2 nucleic acid detection we compared several commercially available RNA extraction methods: QIAamp Viral RNA Mini Kit (QIAGEN), the recently developed RNAdvance Blood (Beckman) and Mag-Bind Viral DNA/RNA 96 Kit (Omega Bio-tek). We also compared different 1-step RT-qPCR Master Mix brands: TaqMan™ Fast Virus 1-Step Master Mix (ThermoFisher Scientific), qPCRBIO Probe 1-Step Go Lo-ROX (PCR Biosystems) and Luna® Universal Probe One-Step RT-qPCR Kit (NEB). We used the Centre for Disease Control (CDC) recommended primers that detect two regions of the viral N gene as well as those that detect the RdRP gene region as per Public Health England (PHE) guidelines (Charité/WHO/PHE). Our data show that the RNA extraction methods provide similar results. Amongst the qPCR reagents tested, TaqMan™ Fast Virus 1-Step Master Mix and Luna® Universal Probe One-Step RT-qPCR Kit proved most sensitive. The N1 and N2 primer-probes provide a more reliable detection than the RdRP_SARSr primer-probe set, particularly in samples with low viral titres. Importantly, we have implemented a protocol using heat inactivation and demonstrate that it has minimal impact on the sensitivity of the qPCR in clinical samples – potentially making SARS-CoV-2 testing portable to settings that do not have CL-3 facilities.In summary, we provide several testing pipelines that can be easily implemented in other laboratories and have made all our protocols and SOPs freely available at https://osf.io/uebvj/.

scholarly journals Relative Sensitivity of Common Target Genes For The Detection of SARS-Cov-2 In Real Time-PCR

2021 ◽  
Author(s):  
Reza Valadan ◽  
Soheila Golchin ◽  
Reza Alizadeh-Navaei ◽  
Mohammadreza Haghshenas ◽  
Mehryar Zargari ◽  
...  
Keyword(s):  
Real Time ◽  
Target Genes ◽  
False Negative ◽  
Rna Extraction ◽  
Host Cells ◽  
N Gene ◽  
Clinical Samples ◽  
Human Beings ◽  
Gene Expressions ◽  
Mazandaran Province

Abstract SARS-CoV-2(COVID-19) currently is the main cause of the severe acute respiratory disease and fatal outcomes in human beings worldwide. Several genes are used as targets for the detection of SARS-CoV-2, including the RDRP, N, and E genes. The present study aimed to determine the RDRP, N, and E genes expressions of SARS-CoV- 2 in clinical samples. For this purpose, 100 SARS-CoV-2 positive samples were collected from diagnostic laboratories of Mazandaran province, Iran. After RNA extraction, the real time RT-PCR assay was performed for differential gene expressions’ analysis of N, E, and RDRP. The CT values for N, RDRP, and E targets of 100 clinical samples for identifying SARS-CoV-2 were then evaluated using qRT-PCR. This result suggests N gene as a potential target for the detection of the SARS‐CoV‐2, since it was observed to be highly expressed in the nasopharyngeal or oropharynges of COVID-19 patients (P < 0.0001). Herein, we showed that SARS-CoV- 2 genes were differentially expressed in the host cells. Therefore, to reduce obtaining false negative results and to increase the sensitivity of the available diagnostic tests, the target genes should be carefully selected based on the most expressed genes in the cells.

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