Influenza and respiratory syncytial virus detection in clinical specimens without nucleic acid extraction using FOCUS direct disc assay is substantially equivalent to the traditional methods and the FOCUS nucleic acid extraction–dependent RT-PCR assay

Abstract Background Detection of SARS-CoV-2 viral RNA is important for the diagnosis and management of COVID-19. Methods We present a clinical validation of a reverse transcription PCR (RT-PCR) assay for the SARS-CoV-2 nucleocapsid (N1) gene. Off-board lysis on an automated nucleic acid extraction system was optimized with endemic coronaviruses (OC43 and NL63). Genomic RNA and SARS-CoV-2 RNA in a recombinant viral protein coat were used as control materials and compared for recovery from nucleic acid extraction. Results Nucleic acid extraction showed decreased recovery of endemic Coronavirus in vitro transcribed RNA (NL63) compared with attenuated virus (OC43). SARS-CoV-2 RNA had more reliable recovery from extraction through amplification than genomic RNA. Recovery of genomic RNA was improved by combining lysis buffer with clinical matrix before adding RNA. The RT-PCR assay demonstrated 100% in silico sensitivity and specificity. The accuracy across samples was 100% (75 of 75). Precision studies showed 100% intra-run, inter-run, and inter-technologist concordance. The limit of detection was 264 copies per milliliter (estimated 5 copies per reaction; 35.56 mean threshold cycle value). Conclusions This SARS-CoV-2 assay demonstrates appropriate characteristics for use under an Emergency Use Authorization. Endemic coronavirus controls were useful in optimizing the extraction procedure. In the absence of live or attenuated virus, recombinant virus in a protein coat is an appropriate control specimen type for assay validation during a pandemic.

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Sodium sulphite inhibition of potato and cherry polyphenolics in nucleic acid extraction for virus detection by RT-PCR

Journal of Virological Methods ◽

10.1016/s0166-0934(01)00391-3 ◽

2002 ◽

Vol 99 (1-2) ◽

pp. 123-131 ◽

Cited By ~ 50

Author(s):

R.P Singh ◽

X Nie ◽

M Singh ◽

R Coffin ◽

P Duplessis

Keyword(s):

Nucleic Acid ◽

Virus Detection ◽

Sodium Sulphite ◽

Acid Extraction ◽

Rt Pcr ◽

Nucleic Acid Extraction

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Multicenter Clinical Evaluation of the Alere i Respiratory Syncytial Virus Isothermal Nucleic Acid Amplification Assay

Journal of Clinical Microbiology ◽

10.1128/jcm.01777-17 ◽

2017 ◽

Vol 56 (3) ◽

Cited By ~ 4

Author(s):

Ferdaus Hassan ◽

Lindsay M. Hays ◽

Aleta Bonner ◽

Bradley J. Bradford ◽

Ruffin Franklin ◽

...

Keyword(s):

Respiratory Syncytial Virus ◽

Nucleic Acid ◽

Care Setting ◽

Point Of Care ◽

Nucleic Acid Amplification ◽

Rt Pcr ◽

Pcr Assay ◽

Isothermal Nucleic Acid Amplification ◽

Syncytial Virus ◽

Respiratory Specimens

ABSTRACTThe Alere i respiratory syncytial virus (RSV) assay is an isothermal nucleic acid amplification test capable of detecting RSV directly from respiratory specimens, with results being available in ≤13 min after test initiation. The objective of this study was to evaluate the performance characteristics of the Alere i RSV assay in a point-of-care setting by using direct nasopharyngeal (NP) swab specimens (direct NP) and nasopharyngeal swab specimens eluted and transported in viral transport medium (VTM NP). The study was a prospective, multicenter, clinical trial conducted at 9 sites across the United States to evaluate the clinical performance of the Alere i RSV assay with respiratory specimens obtained from both children (age, <18 years) and older adults (age, >60 years). The performance of the Alere i RSV assay was compared with that of the reference method, the Prodesse ProFlu+ real-time reverse transcriptase PCR (RT-PCR) assay. All specimens with discrepant test results were tested further by a second FDA-cleared PCR assay (the Verigene respiratory virus plus nucleic acid test; Luminex Inc., TX). A total of 554 subjects with signs and symptoms of respiratory infections were enrolled, and respiratory samples were collected in this study. In comparison with the ProFlu+ real-time RT-PCR, the overall sensitivity and specificity of Alere i RSV assay for the detection of RSV were 98.6% (95% confidence interval [CI], 94.4 to 99.7%) and 98.0% (95% CI, 95.8 to 99.1%), respectively, for direct NP and 98.6% (95% CI, 94.4 to 99.7%) and 97.8% (95% CI, 95.5 to 98.9%), respectively, for VTM NP. The Alere i RSV is a highly sensitive and specific molecular assay ideal for rapid RSV detection in patients in the point-of-care setting due to its minimal hands-on time and rapid result availability.

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Differing Effects of Standard and Harsh Nucleic Acid Extraction Procedures on Diagnostic Helminth Real-Time PCRs Applied to Human Stool Samples

Pathogens ◽

10.3390/pathogens10020188 ◽

2021 ◽

Vol 10 (2) ◽

pp. 188

Author(s):

Tanja Hoffmann ◽

Andreas Hahn ◽

Jaco J. Verweij ◽

Gérard Leboulle ◽

Olfert Landt ◽

...

Keyword(s):

Nucleic Acid ◽

Real Time ◽

Real Time Pcr ◽

Acid Extraction ◽

Nucleic Acid Extraction ◽

Pcr Assay ◽

Bead Beating ◽

Stool Samples ◽

Pcr Assays ◽

Human Stool

This study aimed to assess standard and harsher nucleic acid extraction schemes for diagnostic helminth real-time PCR approaches from stool samples. A standard procedure for nucleic acid extraction from stool and a procedure including bead-beating as well as proteinase K digestion were compared with group-, genus-, and species-specific real-time PCR assays targeting helminths and nonhelminth pathogens in human stool samples. From 25 different in-house and commercial helminth real-time PCR assays applied to 77 stool samples comprising 67 historic samples and 10 external quality assessment scheme samples positively tested for helminths, higher numbers of positive test results were observed after bead-beating-based nucleic acid extraction for 5/25 (20%) real-time PCR assays irrespective of specificity issues. Lower cycle threshold values were observed for one real-time PCR assay after the standard extraction scheme, and for four assays after the bead-beating-based scheme. Agreement between real-time PCR results after both nucleic acid extraction strategies according to Cohen’s kappa ranged from poor to almost perfect for the different assays. Varying agreement was observed in eight nonhelminth real-time PCR assays applied to 67 historic stool samples. The study indicates highly variable effects of harsh nucleic acid extraction approaches depending on the real-time PCR assay used.

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Evaluation of an Automated High-Throughput Liquid-Based RNA Extraction Platform on Pooled Nasopharyngeal or Saliva Specimens for SARS-CoV-2 RT-PCR

Viruses ◽

10.3390/v13040615 ◽

2021 ◽

Vol 13 (4) ◽

pp. 615

Author(s):

Allen Wing-Ho Chu ◽

Cyril Chik-Yan Yip ◽

Wan-Mui Chan ◽

Anthony Chin-Ki Ng ◽

Dream Lok-Sze Chan ◽

...

Keyword(s):

Nucleic Acid ◽

High Throughput ◽

Rna Extraction ◽

Nasopharyngeal Swab ◽

Acid Extraction ◽

Rt Pcr ◽

Nucleic Acid Extraction ◽

Suitable Alternative ◽

Pcr Inhibitors ◽

Pcr Targeting

SARS-CoV-2 RT-PCR with pooled specimens has been implemented during the COVID-19 pandemic as a cost- and manpower-saving strategy for large-scale testing. However, there is a paucity of data on the efficiency of different nucleic acid extraction platforms on pooled specimens. This study compared a novel automated high-throughput liquid-based RNA extraction (LRE) platform (PHASIFYTM) with a widely used magnetic bead-based total nucleic acid extraction (MBTE) platform (NucliSENS® easyMAG®). A total of 60 pools of nasopharyngeal swab and 60 pools of posterior oropharyngeal saliva specimens, each consisting of 1 SARS-CoV-2 positive and 9 SARS-CoV-2 negative specimens, were included for the comparison. Real-time RT-PCR targeting the SARS-CoV-2 RdRp/Hel gene was performed, and GAPDH RT-PCR was used to detect RT-PCR inhibitors. No significant differences were observed in the Ct values and overall RT-PCR positive rates between LRE and MBTE platforms (92.5% (111/120] vs 90% (108/120]), but there was a slightly higher positive rate for LRE (88.3% (53/60]) than MBTE (81.7% (49/60]) among pooled saliva. The automated LRE method is comparable to a standard MBTE method for the detection of SAR-CoV-2 in pooled specimens, providing a suitable alternative automated extraction platform. Furthermore, LRE may be better suited for pooled saliva specimens due to more efficient removal of RT-PCR inhibitors.

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