scholarly journals Pooling of Upper Respiratory Specimens Using a SARS-CoV-2 Real-time RT-PCR Assay Authorized for Emergency Use in Low-Prevalence Populations for High-Throughput Testing

2020 ◽  
Vol 7 (11) ◽  
Author(s):  
Gwynngelle A Borillo ◽  
Ron M Kagan ◽  
Russell E Baumann ◽  
Boris M Fainstein ◽  
Lamela Umaru ◽  
...  
Keyword(s):  
Real Time ◽  
False Negative ◽  
False Negative Rate ◽  
Nucleic Acid Amplification ◽  
Rt Pcr ◽  
Pooled Testing ◽  
Negative Results ◽  
Single Positive ◽  
Upper Respiratory ◽  
Respiratory Specimens

Abstract Background Nucleic acid amplification testing is a critical tool for addressing the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic. Specimen pooling can increase throughput and conserve testing resources but requires validation to ensure that reduced sensitivity does not increase the false-negative rate. We evaluated the performance of a real-time reverse transcription polymerase chain reaction (RT-PCR) test authorized by the US Food and Drug Administration (FDA) for emergency use for pooled testing of upper respiratory specimens. Methods Positive specimens were selected from 3 prevalence groups, 1%–3%, >3%–6%, and >6%–10%. Positive percent agreement (PPA) was assessed by pooling single-positive specimens with 3 negative specimens; performance was assessed using Passing-Bablok regression. Additionally, we assessed the distributions of RT-PCR cycle threshold (Ct) values for 3091 positive specimens. Results PPA was 100% for the 101 pooled specimens. There was a linear relationship between Ct values for pooled and single-tested specimens (r = 0.96–0.99; slope ≈ 1). The mean pooled Ct shifts at 40 cycles were 2.38 and 1.90, respectively, for the N1 and N3 targets. The median Cts for 3091 positive specimens were 25.9 (N1) and 24.7 (N3). The percentage of positive specimens with Cts between 40 and the shifted Ct was 1.42% (N1) and 0.0% (N3). Conclusions Pooled and individual testing of specimens positive for SARS-CoV-2 demonstrated 100% agreement, which demonstrates the viability of pooled specimens for SARS-COV-2 testing using a dual-target RT-PCR system. Pooled specimen testing can help increase testing capacity for SARS-CoV-2 with a low risk of false-negative results.

scholarly journals Establishment and Validation of RNA-Based Predictive Models for Understanding Survival of Vibrio parahaemolyticus in Oysters Stored at Low Temperatures

2017 ◽  
Vol 83 (6) ◽  
Author(s):  
Chao Liao ◽  
Yong Zhao ◽  
Luxin Wang
Keyword(s):  
Real Time ◽  
Predictive Models ◽  
Vibrio Parahaemolyticus ◽  
False Negative ◽  
Bacterial Inactivation ◽  
Rt Pcr ◽  
Content Type ◽  
Low Temperature Storage ◽  
Reverse Transcription Pcr ◽  
Negative Results

ABSTRACT This study developed RNA-based predictive models describing the survival of Vibrio parahaemolyticus in Eastern oysters (Crassostrea virginica) during storage at 0, 4, and 10°C. Postharvested oysters were inoculated with a cocktail of five V. parahaemolyticus strains and were then stored at 0, 4, and 10°C for 21 or 11 days. A real-time reverse transcription-PCR (RT-PCR) assay targeting expression of the tlh gene was used to evaluate the number of surviving V. parahaemolyticus cells, which was then used to establish primary molecular models (MMs). Before construction of the MMs, consistent expression levels of the tlh gene at 0, 4, and 10°C were confirmed, and this gene was used to monitor the survival of the total V. parahaemolyticus cells. In addition, the tdh and trh genes were used for monitoring the survival of virulent V. parahaemolyticus. Traditional models (TMs) were built based on data collected using a plate counting method. From the MMs, V. parahaemolyticus populations had decreased 0.493, 0.362, and 0.238 log10 CFU/g by the end of storage at 0, 4, and 10°C, respectively. Rates of reduction of V. parahaemolyticus shown in the TMs were 2.109, 1.579, and 0.894 log10 CFU/g for storage at 0, 4, and 10°C, respectively. Bacterial inactivation rates (IRs) estimated with the TMs (−0.245, −0.152, and −0.121 log10 CFU/day, respectively) were higher than those estimated with the MMs (−0.134, −0.0887, and −0.0732 log10 CFU/day, respectively) for storage at 0, 4, and 10°C. Higher viable V. parahaemolyticus numbers were predicted using the MMs than using the TMs. On the basis of this study, RNA-based predictive MMs are the more accurate and reliable models and can prevent false-negative results compared to TMs. IMPORTANCE One important method for validating postharvest techniques and for monitoring the behavior of V. parahaemolyticus is to establish predictive models. Unfortunately, previous predictive models established based on plate counting methods or on DNA-based PCR can underestimate or overestimate the number of surviving cells. This study developed and validated RNA-based molecular predictive models to describe the survival of V. parahaemolyticus in oysters during low-temperature storage (0, 4, and 10°C). The RNA-based predictive models show the advantage of being able to count all of the culturable, nonculturable, and stressed cells. By using primers targeting the tlh gene and pathogenesis-associated genes (tdh and trh), real-time RT-PCR can evaluate the total surviving V. parahaemolyticus population as well as differentiate the pathogenic ones from the total population. Reliable and accurate predictive models are very important for conducting risk assessment and management of pathogens in food.

scholarly journals Reducing False Negative PCR Test for COVID-19

2020 ◽  
Vol 9 (3) ◽  
pp. 408-410
Author(s):  
Fatemeh Bahreini ◽  
Rezvan Najafi ◽  
Razieh Amini ◽  
Salman Khazaei ◽  
Saeid Bashirian
Keyword(s):  
Polymerase Chain Reaction ◽  
Real Time ◽  
False Negative ◽  
Rt Pcr ◽  
Chain Reaction ◽  
Creative Commons ◽  
Negative Results ◽  
False Negative Results ◽  
Polymerase Chain ◽  
Pcr Test

As the SARS-CoV-2 (COVID-19) pandemic spreads rapidly, there is need for a diagnostic test with high accuracy to detect infected individuals especially those without symptoms. Real-time polymerase chain reaction (RT-PCR) is a common molecular test for diagnosing SARS-CoV-2. If some factors are not taken into consideration when performing this test, it can have a relatively large number of false negative results. In this article, we discuss important considerations that could lead to false negative test reduction. Key words: • SARS-CoV-2 • COVID-19 • Real time polymerase chain reaction • RT-PCR test • Diagnosis • False negatives • Genetics • Emerging disease   Copyright © 2020 Bahreini et al. Published by Global Health and Education Projects, Inc. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0)which permits unrestricted use, distribution, and reproduction in any medium, provided the original work, first published in this journal, is properly cited.

scholarly journals Avoiding COVID-19 Hospital Outbreaks: RT-PCR Swab and Clinical Assessment

2021 ◽  
Author(s):  
Luca Allievi ◽  
Amedeo Bongarzoni ◽  
Guido Tassinario ◽  
Stefano Carugo
Keyword(s):  
Clinical Assessment ◽  
False Negative ◽  
False Negative Rate ◽  
High Specificity ◽  
Diagnostic Process ◽  
Rt Pcr ◽  
Negative Results ◽  
High False Negative Rate ◽  
Degree Of Confidence ◽  
Low Sensitivity

Nasopharyngeal RT-PCR swab test for COVID-19 diagnosis has a high specificity but also a low sensitivity. The high false-negative rate and the overconfidence in negative results sometimes lead to hospital outbreaks. Therefore, we recommend always integrating the clinical assessment in the diagnostic process, mostly after the test, to determine what degree of confidence can be attributed to a negative result.

scholarly journals Pooling Upper Respiratory Specimens for Rapid Mass Screening of COVID-19 by Real-Time RT-PCR

2020 ◽  
Vol 26 (10) ◽  
pp. 2469-2472
Author(s):  
So Yeon Kim ◽  
Jaehyeon Lee ◽  
Heungsup Sung ◽  
Hyukmin Lee ◽  
Myung Guk Han ◽  
...  
Keyword(s):  
Real Time ◽  
Mass Screening ◽  
Rt Pcr ◽  
Upper Respiratory ◽  
Rapid Mass ◽  
Respiratory Specimens

scholarly journals Serological immunochromatographic approach in diagnosis with SARS-CoV-2 infected COVID-19 patients

2020 ◽  
Author(s):  
Yunbao Pan ◽  
Xinran Li ◽  
Gui Yang ◽  
Junli Fan ◽  
Yueting Tang ◽  
...  
Keyword(s):  
Real Time ◽  
Early Stage ◽  
False Negative ◽  
False Negative Rate ◽  
Intermediate Stage ◽  
Rt Pcr ◽  
Igg Antibody ◽  
Blood Samples ◽  
Icg Strip ◽  
Stage 1

AbstractAn outbreak of new coronavirus SARS-CoV-2 was occurred in Wuhan, China and rapidly spread to other cities and nations. The standard diagnostic approach that widely adopted in the clinic is nuclear acid detection by real-time RT-PCR. However, the false-negative rate of the technique is unneglectable and serological methods are urgently warranted. Here, we presented the colloidal gold-based immunochromatographic (ICG) strip targeting viral IgM or IgG antibody and compared it with real-time RT-PCR. The sensitivity of ICG assay with IgM and IgG combinatorial detection in nuclear acid confirmed cases were 11.1%, 92.9% and 96.8% at the early stage (1-7 days after onset), intermediate stage (8-14 days after onset), and late stage (more than 15 days), respectively. The ICG detection capacity in nuclear acid-negative suspected cases was 43.6%. In addition, the consistencies of whole blood samples with plasma were 100% and 97.1% in IgM and IgG strips, respectively. In conclusion, serological ICG strip assay in detecting SARS-CoV-2 infection is both sensitive and consistent, which is considered as an excellent supplementary approach in clinical application.

scholarly journals False-negative results in Real-Time PCR (RT-PCR) for meningococcal disease diagnosis

2013 ◽  
Author(s):  
Lucila Okuyama FUKASAWA ◽  
Maria Gisele GONÇALVES ◽  
Fabio Takenori HIGA ◽  
Maristela Marques SALGADO ◽  
Ana Paula Silva de LEMOS ◽  
...  
Keyword(s):  
Real Time ◽  
Meningococcal Disease ◽  
Real Time Pcr ◽  
False Negative ◽  
Disease Diagnosis ◽  
Rt Pcr ◽  
Negative Results ◽  
False Negative Results

scholarly journals Comparison of real-time RT-PCR and RT-PCR/MALDI-TOF methods for SARS-CoV-2 detection in saliva

2021 ◽  
Vol 156 (Supplement_1) ◽  
pp. S9-S9
Author(s):  
Matthew M Hernandez ◽  
Radhika Banu ◽  
Paras Shrestha ◽  
Armi Patel ◽  
Feng Chen ◽  
...  
Keyword(s):  
Real Time ◽  
Limit Of Detection ◽  
High Sensitivity ◽  
N Gene ◽  
Rt Pcr ◽  
Upper Respiratory ◽  
High Level ◽  
Respiratory Specimens ◽  
Pcr Test ◽  
Roche Cobas

Abstract Background The coronavirus disease 2019 pandemic has accelerated the need for rapid validation and implementation of assays for detection of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) in diagnostic specimens. Multiple molecular methods have received emergency use authorization by the U.S. Food and Drug Administration for detection of SARS-CoV-2 in upper respiratory specimens, with testing of nasopharyngeal (NP) specimens serving as the foundation for these assays. However, supply chain constraints and the need for improved ease and safety of collection have prompted consideration of other specimen types as alternatives to NP specimens for detection of SARS-CoV-2. Here, we compared two methods for SARS-CoV-2 detection in saliva: the Roche cobas® 6800 SARS-CoV-2 real-time RT-PCR Test (“Roche”), which tests for viral ORF1ab (target 1, T1) and envelope E genes (target 2, T2); and the Agena Biosciences MassARRAY® SARS-CoV-2 Panel/MassARRAY® System (“Agena”), which tests for targets in the ORF1ab gene (ORF1, Orf1ab) and nucleocapsid N gene (N1, N2, N3). Methods Sixty saliva specimens collected within 48 hours of SARS-CoV-2 detection in an upper respiratory (anterior nares or NP) specimen from the same individual were tested in both the Roche and Agena platforms. Each system was evaluated for overall detection results and agreement with results of matched upper respiratory specimens. In addition, we determined the limit of detection (LoD) for each system and its component targets using an in-house SARS-CoV-2 standard generated from pooled positive saliva specimens quantitated against a commercially available standard (ZeptoMetrix NATSARS(COV2)-ERC). Results Both platforms demonstrated a similarly high sensitivity (97%) and specificity (100%) when compared to matched patient upper respiratory specimens and had high agreement with one another (Cohen’s κ = 0.9321, p = 2.6x10-13). Overall, the LoD (copies/mL) for the Roche assay was four times lower than that of Agena for saliva specimens (390.6 v. 1562.5). Furthermore, we determined that the LoD differed among the target components of each assay. The experimental LoD was comparable across Roche targets, but probit analyses indicate T2 has greater sensitivity (LoD: 228.6), Of the five Agena targets, the N2 target had the lowest LoD (1562.5). Conclusions In sum, we demonstrate that saliva is an acceptable specimen for testing in both the Roche cobas® 6800 SARS-CoV-2 real-time RT-PCR Test and the Agena Biosciences MassARRAY® SARS-CoV-2 Panel/MassARRAY® System, and both provide sensitive and specific detection of SARS-CoV-2 in saliva specimens. Although there was a high level of agreement between platforms, the LoD was lower for the Roche compared to the Agena assay with T2 and N2 being the most sensitive targets on each platform, respectively. The addition of saliva as an acceptable specimen and understanding the sensitivity for testing on these platforms can further inform public health measures for screening and detection to combat the pandemic.

scholarly journals Amplification of human β-glucoronidase gene for appraising the accuracy of negative SARS-CoV-2 RT-PCR results in upper respiratory tract specimens

2020 ◽  
Author(s):  
Eliseo Albert ◽  
Blanca Ferrer ◽  
Ignacio Torres ◽  
Alicia Serrano ◽  
Maria Jesus Alcaraz ◽  
...  
Keyword(s):  
Respiratory Tract ◽  
Operating Characteristic ◽  
False Negative ◽  
Upper Respiratory Tract ◽  
Rt Pcr ◽  
Roc Curve Analysis ◽  
True Negative ◽  
Negative Results ◽  
Upper Respiratory ◽  
Polymerase Chain

Real-time reverse transcription polymerase-chain reaction (RT-PCR) is the mainstay of Covid-19 diagnosis. False-negative RT-PCR results may hamper clinical management of patients and hinder the adoption of epidemiological measures to control the pandemic. The current study was aimed at assessing whether amplification of β-glucoronidase (GUSB) gene would help estimate the accuracy of SARS-CoV-2 RT-PCR negative results in upper respiratory tract (URT) specimens. URT specimens that tested negative by SARS-CoV-2 RT-PCR displayed higher GUSB RT-PCR cycle thresholds (CT) (P=0.070) than those testing positive (median, 30.7; range, 27.0-40.0, and median 29.7; range 25.5-36.8, respectively), this reflecting poorer cellularity. Receiver operating characteristic (roc) curve analysis indicated that a CT threshold of 31.2 discriminated best between positive and negative SARS CoV-2 RT-PCRs (area under a curve, 0.66; 95% CI, 0.50-0.81; P=0.08). This cut-off yielded a true negative ratio of 89% and accuracy of 70%. The data suggested that amplification of the GUSB gene by RT-PCR may help to appraise the accuracy of negative SARS-CoV-2 RT-PCR results in patients in whom Covid-19 is eventually diagnosed.

scholarly journals Multi-site Evaluation of SARS-CoV-2 Spike Mutation Detection Using a Multiplex Real-time RT-PCR Assay

2021 ◽  
Author(s):  
Carolin Bier ◽  
Anke Edelmann ◽  
Kathrin Theil ◽  
Rolf Schwarzer ◽  
Maria Deichner ◽  
...  
Keyword(s):  
Real Time ◽  
Limit Of Detection ◽  
False Negative ◽  
Analytical Sensitivity ◽  
Test Results ◽  
Rt Pcr ◽  
Pcr Assay ◽  
Clinical Specimens ◽  
Negative Results ◽  
Global Pandemic

Background. SARS-CoV-2 causes COVID-19, which can be fatal and is responsible for a global pandemic. Variants with increased transmissibility or the potential to evade immunity have emerged and represent a threat to global pandemic control. Variants of concern (VOC) can be identified by sequencing of viral RNA, or by more rapid methods for detection of subsets of signature mutations. Methods. We developed a multiplex, real-time RT-PCR assay (cobas SARS-CoV-2 Variant Set 1) for the qualitative detection and differentiation of three key SARS-CoV-2 mutations in the viral spike protein: del 69-70, E484K and N501Y. Analytical sensitivity and accuracy were evaluated at three testing sites using clinical specimens from patients infected with SARS-CoV-2 variants belonging to several different lineages, including B.1.1.7, B.1.351, and P.1. Results. The limit of detection for E484K was between 180 and 620 IU/mL for the three different isolates tested. For N501Y, the LOD was between 270 and 720 IU/mL (five isolates), while for del 69-70, it was 80 - 92 IU/mL (two isolates). Valid test results were obtained with all clinical specimens that were positive using routine diagnostic tests. Compared to sequencing (Sanger and next-generation), test results were 100% concordant at all three loci; no false positive or false negative results were observed. Conclusions. Data collected at three independent laboratories indicates excellent performance and concordance of cobas SARS-CoV-2 Variant Set 1 with sequencing. New sets of primers and probes that target additional loci can be rapidly deployed in response to the identification of other emerging variants.

scholarly journals Nucleocapsid (N) Gene Mutations of SARS-CoV-2 Can Affect Real-Time RT-PCR Diagnostic and Impact False-Negative Results

Viruses ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 2474
Author(s):  
Jéssika Cristina Chagas Lesbon ◽  
Mirele Daiana Poleti ◽  
Elisângela Chicaroni de Mattos Oliveira ◽  
José Salvatore Leister Patané ◽  
Luan Gaspar Clemente ◽  
...  
Keyword(s):  
Real Time ◽  
False Negative ◽  
Gene Mutations ◽  
Sao Paulo ◽  
N Gene ◽  
São Paulo ◽  
Rt Pcr ◽  
Nucleocapsid Gene ◽  
Negative Results ◽  
False Negative Results

The current COVID-19 pandemic demands massive testing by Real-time RT-PCR (Reverse Transcription Polymerase Chain Reaction), which is considered the gold standard diagnostic test for the detection of the SARS-CoV-2 virus. However, the virus continues to evolve with mutations that lead to phenotypic alterations as higher transmissibility, pathogenicity or vaccine evasion. Another big issue are mutations in the annealing sites of primers and probes of RT-PCR diagnostic kits leading to false-negative results. Therefore, here we identify mutations in the N (Nucleocapsid) gene that affects the use of the GeneFinder COVID-19 Plus RealAmp Kit. We sequenced SARS-CoV-2 genomes from 17 positive samples with no N gene detection but with RDRP (RNA-dependent RNA polymerase) and E (Envelope) genes detection, and observed a set of three different mutations affecting the N detection: a deletion of 18 nucleotides (Del28877-28894), a substitution of GGG to AAC (28881-28883) and a frameshift mutation caused by deletion (Del28877-28878). The last one cause a deletion of six AAs (amino acids) located in the central intrinsic disorder region at protein level. We also found this mutation in 99 of the 14,346 sequenced samples by the Sao Paulo state Network for Pandemic Alert of Emerging SARS-CoV-2 variants, demonstrating the circulation of the mutation in Sao Paulo, Brazil. Continuous monitoring and characterization of mutations affecting the annealing sites of primers and probes by genomic surveillance programs are necessary to maintain the effectiveness of the diagnosis of COVID-19.

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