scholarly journals Clinical Evaluation of Self-Collected Saliva by Quantitative Reverse Transcription-PCR (RT-qPCR), Direct RT-qPCR, Reverse Transcription–Loop-Mediated Isothermal Amplification, and a Rapid Antigen Test To Diagnose COVID-19

2020 ◽  
Vol 58 (9) ◽  
Author(s):  
Mayu Nagura-Ikeda ◽  
Kazuo Imai ◽  
Sakiko Tabata ◽  
Kazuyasu Miyoshi ◽  
Nami Murahara ◽  
...  
Keyword(s):  
High Throughput ◽  
Reverse Transcription ◽  
Diagnostic Tests ◽  
Isothermal Amplification ◽  
Viral Rna ◽  
Molecular Diagnostic ◽  
Antigen Test ◽  
Loop Mediated Isothermal Amplification ◽  
Quantitative Reverse Transcription Pcr ◽  
Reverse Transcription Pcr

ABSTRACT The clinical performances of six molecular diagnostic tests and a rapid antigen test for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) were clinically evaluated for the diagnosis of coronavirus disease 2019 (COVID-19) in self-collected saliva. Saliva samples from 103 patients with laboratory-confirmed COVID-19 (15 asymptomatic and 88 symptomatic) were collected on the day of hospital admission. SARS-CoV-2 RNA in saliva was detected using a quantitative reverse transcription-PCR (RT-qPCR) laboratory-developed test (LDT), a cobas SARS-CoV-2 high-throughput system, three direct RT-qPCR kits, and reverse transcription–loop-mediated isothermal amplification (RT-LAMP). The viral antigen was detected by a rapid antigen immunochromatographic assay. Of the 103 samples, viral RNA was detected in 50.5 to 81.6% of the specimens by molecular diagnostic tests, and an antigen was detected in 11.7% of the specimens by the rapid antigen test. Viral RNA was detected at significantly higher percentages (65.6 to 93.4%) in specimens collected within 9 days of symptom onset than in specimens collected after at least 10 days of symptoms (22.2 to 66.7%) and in specimens collected from asymptomatic patients (40.0 to 66.7%). Self-collected saliva is an alternative specimen option for diagnosing COVID-19. The RT-qPCR LDT, a cobas SARS-CoV-2 high-throughput system, direct RT-qPCR kits (except for one commercial kit), and RT-LAMP showed sufficient sensitivities in clinical use to be selectively used in clinical settings and facilities. The rapid antigen test alone is not recommended for an initial COVID-19 diagnosis because of its low sensitivity.

scholarly journals Clinical evaluation of self-collected saliva by RT-qPCR, direct RT-qPCR, RT-LAMP, and a rapid antigen test to diagnose COVID-19

2020 ◽  
Author(s):  
Mayu Ikeda ◽  
Kazuo Imai ◽  
Sakiko Tabata ◽  
Kazuyasu Miyoshi ◽  
Nami Murahara ◽  
...  
Keyword(s):  
High Throughput ◽  
Reverse Transcription ◽  
Symptom Onset ◽  
Diagnostic Tests ◽  
Clinical Performance ◽  
Viral Rna ◽  
Molecular Diagnostic ◽  
Clinical Use ◽  
Antigen Test ◽  
Asymptomatic Patients

AbstractBackgroundThe clinical performance of six molecular diagnostic tests and a rapid antigen test for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) were clinically evaluated for the diagnosis of coronavirus disease 2019 (COVID-19) in self-collected saliva.MethodsSaliva samples from 103 patients with laboratory-confirmed COVID-19 (15 asymptomatic and 88 symptomatic) were collected on the day of hospital admission. SARS-CoV-2 RNA in saliva was detected using a quantitative reverse-transcription polymerase chain reaction (RT-qPCR) laboratory-developed tes (LDT), a cobas SARS-CoV-2 high-throughput system, three direct RT-qPCR kits, and reverse-transcription loop mediated isothermal amplification (RT-LAMP). Viral antigen was detected by a rapid antigen immunochromatographic assay.ResultsOf the 103 samples, viral RNA was detected in 50.5–81.6% of the specimens by molecular diagnostic tests and an antigen was detected in 11.7% of the specimens by the rapid antigen test. Viral RNA was detected at a significantly higher percentage (65.6–93.4%) in specimens collected within 9 d of symptom onset compared to that of specimens collected after at least 10 d of symptom onset (22.2–66.7%) and that of asymptomatic patients (40.0–66.7%). Viral RNA was more frequently detected in saliva from males than females.ConclusionsSelf-collected saliva is an alternative specimen diagnosing COVID-19. LDT RT-qPCR, cobas SARS-CoV-2 high-throughput system, direct RT-qPCR except for one commercial kit, and RT-LAMP showed sufficient sensitivity in clinical use to be selectively used according to clinical settings and facilities. The rapid antigen test alone is not recommended for initial COVID-19 diagnosis because of its low sensitivity.Key pointsSix molecular diagnostic tests showed equivalent and sufficient sensitivity in clinical use in diagnosing COVID-19 in self-collected saliva samples. However, a rapid SARS-CoV-2 antigen test alone is not recommended for use without further study.

High-Throughput Real-Time Quantitative Reverse Transcription PCR

2006 ◽  
Vol 73 (1) ◽  
pp. 15.8.1-15.8.28 ◽  
Author(s):  
Angie L. Bookout ◽  
Carolyn L. Cummins ◽  
David J. Mangelsdorf ◽  
Jean M. Pesola ◽  
Martha F. Kramer
Keyword(s):  
Real Time ◽  
High Throughput ◽  
Reverse Transcription ◽  
Quantitative Reverse Transcription Pcr ◽  
Reverse Transcription Pcr

DEVELOPMENT AND ASSESSMENT OF A REAGENT KIT FOR RNA DETECTION OF CRIMEAN-CONGO HEMORRHAGIC FEVER VIRUS WITH USING REVERSE TRANSCRIPTION LOOP-MEDIATED ISOTHERMAL AMPLIFICATION METHOD

2019 ◽  
Vol 64 (9) ◽  
pp. 571-577
Author(s):  
V. A. Ternovoi ◽  
Yu. V. Kononova ◽  
A. V. Zaykovskaya ◽  
E. V. Chub ◽  
A. S. Volynkina ◽  
...  
Keyword(s):  
Reverse Transcription ◽  
High Speed ◽  
Hemorrhagic Fever ◽  
Fever Virus ◽  
Isothermal Amplification ◽  
Viral Rna ◽  
Rna Detection ◽  
Crimean Congo Hemorrhagic Fever ◽  
Loop Mediated Isothermal Amplification ◽  
Hemorrhagic Fever Virus

This study presents the results of laboratory trials of the reagent kit for the rapid detection of RNA of the Crimean-Congo hemorrhagic fever virus (CCHFV) using loop-mediated isothermal amplification with reverse transcription (RT-LAMP). The developed RT-LAMP reagent kit was used to detect the CCHFV and showed a sensitivity of 103 GE/ml of viral RNA, which is sufficient for detection of the CCHFV in the early stage of human infections. The kit showed high specificity and no cross-reactivity with viral panel from the State collection of viruses of the FBRI SRC VB «Vector» (arboviruses and hemorrhagic fever viruses). Laboratory trials of the RT-LAMP kit are showed a high analytical and diagnostic sensitivity and specificity for RNA detection of the CCHFV and high speed of the analysis (60-70 min with sample preparation) compared to real-time PCR. Approbation of the kit field version has showed the possibility of setting the RT-LAMP reaction and viral RNA detection without the using of analytical equipments.

scholarly journals Rapid Detection of Novel Coronavirus (COVID-19) by Reverse Transcription-Loop-Mediated Isothermal Amplification

2020 ◽  
Author(s):  
Laura E. Lamb ◽  
Sarah N. Bartolone ◽  
Elijah Ward ◽  
Michael B. Chancellor
Keyword(s):  
Diagnostic Test ◽  
Reverse Transcription ◽  
Simulated Patient ◽  
Isothermal Amplification ◽  
Rapid Screening ◽  
Health Concern ◽  
Loop Mediated Isothermal Amplification ◽  
Qrt Pcr ◽  
Reverse Transcription Pcr ◽  
Novel Coronavirus

AbstractNovel Corona virus (COVID-19 or 2019-nCoV) is an emerging global health concern that requires a rapid diagnostic test. Quantitative reverse transcription PCR (qRT-PCR) is currently the standard for COVID-19 detection; however, Reverse Transcription Loop-Mediated Isothermal Amplification (RT-LAMP) may allow for faster and cheaper field based testing at point-of-risk. The objective of this study was to develop a rapid screening diagnostic test that could be completed in under 30 minutes. Simulated patient samples were generated by spiking serum, urine, saliva, oropharyngeal swabs, and nasopharyngeal swabs with a portion of the COVID-19 nucleic sequence. The samples were tested using RT-LAMP as well as by conventional qRT-PCR. Specificity of the RT-LAMP was evaluated by also testing against other related coronaviruses. RT-LAMP specifically detected COVID-19 in simulated patient samples. This test was performed in under 30 minutes. This approach could be used for monitoring of exposed individuals or potentially aid with screening efforts in the field and potential ports of entry.

scholarly journals Optimization and Clinical Validation of Colorimetric Reverse Transcription Loop-Mediated Isothermal Amplification, a Fast, Highly Sensitive and Specific COVID-19 Molecular Diagnostic Tool That Is Robust to Detect SARS-CoV-2 Variants of Concern

2021 ◽  
Vol 12 ◽  
Author(s):  
Pedro A. Alves ◽  
Ellen G. de Oliveira ◽  
Ana Paula M. Franco-Luiz ◽  
Letícia T. Almeida ◽  
Amanda B. Gonçalves ◽  
...  
Keyword(s):  
Reverse Transcription ◽  
Limit Of Detection ◽  
Quantitative Polymerase Chain Reaction ◽  
Isothermal Amplification ◽  
Alternative Methods ◽  
Molecular Diagnostic ◽  
Clinical Validation ◽  
Rna Detection ◽  
Loop Mediated Isothermal Amplification ◽  
Viral Transport Medium

The coronavirus disease 2019 (COVID-19) pandemic unfolded due to the widespread severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission reinforced the urgent need for affordable molecular diagnostic alternative methods for massive testing screening. We present the clinical validation of a pH-dependent colorimetric reverse transcription loop-mediated isothermal amplification (RT-LAMP) for SARS-CoV-2 detection. The method revealed a limit of detection of 19.3 ± 2.7 viral genomic copies/μL when using RNA extracted samples obtained from nasopharyngeal swabs collected in guanidine-containing viral transport medium. Typical RT-LAMP reactions were performed at 65°C for 30 min. When compared to reverse transcriptase–quantitative polymerase chain reaction (RT-qPCR), up to cycle-threshold (Ct) value 32, RT-LAMP presented 98% [95% confidence interval (CI) = 95.3–99.5%] sensitivity and 100% (95% CI = 94.5–100%) specificity for SARS-CoV-2 RNA detection targeting E and N genes. No cross-reactivity was detected when testing other non–SARS-CoV virus, confirming high specificity. The test is compatible with primary RNA extraction–free samples. We also demonstrated that colorimetric RT-LAMP can detect SARS-CoV-2 variants of concern and variants of interest, such as variants occurring in Brazil named gamma (P.1), zeta (P.2), delta (B.1.617.2), B.1.1.374, and B.1.1.371. The method meets point-of-care requirements and can be deployed in the field for high-throughput COVID-19 testing campaigns, especially in countries where COVID-19 testing efforts are far from ideal to tackle the pandemics. Although RT-qPCR is considered the gold standard for SARS-CoV-2 RNA detection, it requires expensive equipment, infrastructure, and highly trained personnel. In contrast, RT-LAMP emerges as an affordable, inexpensive, and simple alternative for SARS-CoV-2 molecular detection that can be applied to massive COVID-19 testing campaigns and save lives.

scholarly journals Comparative Diagnostic Performance of a Novel Reverse Transcription Loop-Mediated Isothermal Amplification (RT-LAMP) Kit for the Rapid Detection of SARS-CoV-2

Pathogens ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1629
Author(s):  
Alexander Domnich ◽  
Andrea Orsi ◽  
Donatella Panatto ◽  
Vanessa De Pace ◽  
Valentina Ricucci ◽  
...  
Keyword(s):  
Reverse Transcription ◽  
Diagnostic Performance ◽  
Point Of Care ◽  
Lamp Assay ◽  
Laboratory Diagnosis ◽  
Isothermal Amplification ◽  
Molecular Diagnostic ◽  
Rt Pcr ◽  
Laboratory Equipment ◽  
Loop Mediated Isothermal Amplification

Although the reverse transcription-polymerase chain reaction (RT-PCR) is considered a standard-of-care assay for the laboratory diagnosis of SARS-CoV-2, several limitations of this method have been described. Reverse transcription loop-mediated isothermal amplification (RT-LAMP) is an alternative molecular assay and is potentially able to overcome some intrinsic shortcomings of RT-PCR. In this study, we evaluated the diagnostic performance of the novel HG COVID-19 RT-LAMP assay. In this retrospective analysis, a total of 400 routinely collected leftover nasopharyngeal samples with a known RT-PCR result were tested by means of the HG COVID-19 RT-LAMP assay. The overall sensitivity and specificity values of HG COVID-19 RT-LAMP versus RT-PCR were 97.0% (95% CI: 93.6–98.9%) and 98.5% (95% CI: 95.7–99.7%), respectively. Inter-assay agreement was almost perfect (κ = 0.96). Concordance was perfect in samples with high viral loads (cycle threshold < 30). The average time to a positive result on RT-LAMP was 17 min. HG COVID-19 RT-LAMP is a reliable molecular diagnostic kit for detecting SARS-CoV-2, and its performance is comparable to that of RT-PCR. Shorter turnaround times and the possibility of performing molecular diagnostics in the point-of-care setting make it a valuable option for facilities without sophisticated laboratory equipment.

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