scholarly journals Pooled Testing for Expanding COVID-19 Mass Surveillance

2020 ◽  
Vol 14 (3) ◽  
pp. e42-e43 ◽  
Author(s):  
Angela Felicia Sunjaya ◽  
Anthony Paulo Sunjaya
Keyword(s):  
Diagnostic Testing ◽  
Pcr Amplification ◽  
The United States ◽  
Positive Sample ◽  
Pooled Testing ◽  
Blood Banks ◽  
Massive Scale ◽  
Polymerase Chain ◽  
Pool Test ◽  
Mass Surveillance

ABSTRACTDiagnostic testing to identify patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) plays a key role to control the coronavirus disease (COVID-19) pandemic. While several countries have implemented the use of diagnostic testing in a massive scale as a cornerstone for infection control and surveillance, other countries affected by the pandemic are hampered by its limited testing capacity. Pooled testing was first introduced in the 1940s and is now used for screening in blood banks. Testing is done by pooling multiple individual samples together. Only in the case of a positive pool test would individual samples of the pool be tested, thus substantially reducing the number of tests needed. Several studies regarding their use for SARS CoV-2 have been done in the United States, Israel, and Germany. Studies have shown that an individual positive sample can still be detected in pools of up to 32 samples, and possibly even 64 samples, provided that additional polymerase chain reaction (PCR) amplification cycles are conducted with a sensitivity of 96%. Simulation studies to determine optimal pool size and pooling techniques have also been conducted. Based on these studies, pooled testing is shown to be able to detect positive samples with sufficient accuracy and can easily be used with existing equipment and personnel for population-wide screening.

scholarly journals Evaluation of COVID-19 RT-qPCR Test in Multi sample Pools

2020 ◽  
Vol 71 (16) ◽  
pp. 2073-2078 ◽  
Author(s):  
Idan Yelin ◽  
Noga Aharony ◽  
Einat Shaer Tamar ◽  
Amir Argoetti ◽  
Esther Messer ◽  
...  
Keyword(s):  
Quantitative Polymerase Chain Reaction ◽  
False Negative ◽  
Rna Extraction ◽  
False Negative Rate ◽  
Positive Sample ◽  
Recent Emergence ◽  
Single Positive ◽  
Polymerase Chain ◽  
Pool Test ◽  
Current Screening

Abstract Background The recent emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) led to a current pandemic of unprecedented scale. Although diagnostic tests are fundamental to the ability to detect and respond, overwhelmed healthcare systems are already experiencing shortages of reagents associated with this test, calling for a lean immediately applicable protocol. Methods RNA extracts of positive samples were tested for the presence of SARS-CoV-2 using reverse transcription quantitative polymerase chain reaction, alone or in pools of different sizes (2-, 4-, 8-, 16-, 32-, and 64-sample pools) with negative samples. Transport media of additional 3 positive samples were also tested when mixed with transport media of negative samples in pools of 8. Results A single positive sample can be detected in pools of up to 32 samples, using the standard kits and protocols, with an estimated false negative rate of 10%. Detection of positive samples diluted in even up to 64 samples may also be attainable, although this may require additional amplification cycles. Single positive samples can be detected when pooling either after or prior to RNA extraction. Conclusions As it uses the standard protocols, reagents, and equipment, this pooling method can be applied immediately in current clinical testing laboratories. We hope that such implementation of a pool test for coronavirus disease 2019 would allow expanding current screening capacities, thereby enabling the expansion of detection in the community, as well as in close organic groups, such as hospital departments, army units, or factory shifts.

scholarly journals Identification of SARS-CoV-2 in a Proficiency Testing Program

2020 ◽  
Vol 154 (4) ◽  
pp. 475-478
Author(s):  
Daniel C Edson ◽  
Danielle L Casey ◽  
Susan E Harmer ◽  
Frances P Downes
Keyword(s):  
The United States ◽  
Positive Sample ◽  
Test Results ◽  
Rna Detection ◽  
Virus Particles ◽  
Molecular Tests ◽  
P Gene ◽  
Control And Prevention ◽  
Overall Performance ◽  
Polymerase Chain

Abstract Objectives At the onset of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic in the United States, testing was limited to the Centers for Disease Control and Prevention–developed reverse transcription polymerase chain reaction assay. The urgent and massive demand for testing prompted swift development of assays to detect SARS-CoV-2. The objective of this study was to assess the accuracy of these newly developed tests. Methods The American Proficiency Institute sent 2 test samples to 346 clinical laboratories in order to assess the accuracy of SARS-CoV-2 assays. The positive sample, containing 5,175 viral copies/mL, was fully extractable with SARS-CoV-2 viral capsid protein and RNA. The negative sample, with 3,951 viral copies/mL, contained recombinant virus particles with sequences for targeting human RNAase P gene sequences. Results Of the laboratories submitting results, 97.4% (302/310) correctly detected the virus when present and 98.3% (296/301) correctly indicated when the virus was not present. Among incorrect results reported in this proficiency challenge, 76.9% (10/13) were likely related to clerical error. This accounts for 1.6% (10/611) of all reported results. Conclusions Overall performance in this SARS-CoV-2 RNA detection challenge was excellent, providing confidence in the results of these new molecular tests and assurance for the clinical and public health decisions based on these test results.

scholarly journals A Method for Extracting Genomic DNA from Individual Elaphostrongyline (Nematoda: Protostrongylidae) Larvae and Differentiation of Elaphostrongylus Spp. from Parelaphostrongylus Spp. by PCR Assay

2005 ◽  
Vol 17 (6) ◽  
pp. 585-588 ◽  
Author(s):  
Neil B. Chilton ◽  
Florence Huby-Chilton ◽  
Murray W. Lankester ◽  
Alvin A. Gajadhar
Keyword(s):  
Newfoundland And Labrador ◽  
Genomic Dna ◽  
Diagnostic Testing ◽  
Pcr Amplification ◽  
Chain Reaction ◽  
Pcr Assay ◽  
Extraction And Purification ◽  
Veterinary Importance ◽  
Polymerase Chain ◽  
Partial Fragment

This article reports a rapid and effective method for the extraction and purification of genomic DNA (gDNA) from individual first-stage larvae (L1) of elaphostrongyline nematodes that had been stored frozen or fixed in 95% ethanol for 1 to 5 years. The method was highly effective for L1s of all 6 species of elaphostrongylines, based on polymerase chain reaction (PCR) amplification of a partial fragment of the first internal transcribed spacer (ITS-1) of the ribosomal DNA. Differences were detected in the sizes of partial ITS-1 amplicons between the 2 elaphostrongyline genera, Elaphostrongylus and Parelaphostrongylus. The reliability of the ITS-1 PCR assay was tested by using L1s of unknown identity from Newfoundland and Labrador, Canada. The ability to consistently isolate gDNA from individual L1s, together with a simple PCR-based method to distinguish between Parelaphostrongylus and Elaphostrongylus, have important implications for diagnostic testing and for conducting epizootiological studies on these parasites of veterinary importance.

Comparison of Template Preparation Methods from Foods for Amplification of Escherichia coli O157 Shiga-Like Toxins Type I and II DNA by Multiplex Polymerase Chain Reaction

1995 ◽  
Vol 58 (7) ◽  
pp. 722-726 ◽  
Author(s):  
KAREN C. JINNEMAN ◽  
PAULA A. TROST ◽  
WALTER E. HILL ◽  
STEPHEN D. WEAGANT ◽  
JAMES L. BRYANT ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Polymerase Chain Reaction ◽  
Pcr Amplification ◽  
Physiological Saline ◽  
The United States ◽  
Detection Sensitivity ◽  
Type I ◽  
Escherichia Coli O157 ◽  
Chain Reaction ◽  
Polymerase Chain

Escherichia coli O157:H7 has been responsible for several recent food-borne outbreaks in the United States. To protect the public health, it is essential that rapid and sensitive methods be developed for detection of this pathogen in foods. Methods were compared for preparation of template DNA for the polymerase chain reaction (PCR) from enrichments of food homogenates seeded with E. coli O157:H7. Samples were enriched for 6 h at 37°C in modified tryptic soy broth supplemented with vancomycin, cefsulodin, and cefixime. Aliquots of the enrichments (10 ml or 1 ml) were analyzed by either washing twice with physiological saline or incubating with antibodies to O157 coupled to immunomagnetic beads (Dynal®) followed by resuspending and boiling the samples. A portion of the preparation was used in a multiplex PCR to amplify a 274-bp fragment from the sltI gene and a 364-bp fragment from the sltII gene. PCR amplification of 1-ml portions of enrichment broth was successful at inoculation levels of about 10 cells per g of food. Increasing the test sample volume to 10 ml and/or using an immunomagnetic separation step improved the PCR detection sensitivity to about 1 cell per g; the entire analysis can be completed within 12 h.

scholarly journals Pooling of samples for SARS-CoV-2 detection using rapid antigen tests

2021 ◽  
Author(s):  
Nol Salcedo ◽  
Alexander Harmon ◽  
Bobby Brooke Herrera
Keyword(s):  
Positive Sample ◽  
Diagnostic Efficiency ◽  
Rt Pcr ◽  
Middle Income ◽  
Pooled Testing ◽  
Middle Income Countries ◽  
Pooling Strategy ◽  
Polymerase Chain ◽  
Antigen Tests ◽  
Antigen Testing

AbstractWhile molecular assays, such as reverse-transcription polymerase chain reaction (RT- PCR), have been widely used throughout the coronavirus disease 2019 (COVID-19) pandemic, the technique is resource intensive and costly. As a means to reduce costs and expand diagnostic efficiency, pooled testing using RT-PCR has been implemented. However, pooled testing using rapid antigen tests has not been evaluated. Here, we propose a pooling strategy for rapid antigen testing that would significantly expand COVID-19 surveillance, especially for low-to-middle income countries, and schools and workplaces. Our data demonstrate that combining of up to 20 samples per pool can expand surveillance with rapid antigen tests, even if a pool contains only one positive sample.

scholarly journals Pooling of Samples for SARS-CoV-2 Detection Using a Rapid Antigen Test

2021 ◽  
Vol 2 ◽  
Author(s):  
Nol Salcedo ◽  
Alexander Harmon ◽  
Bobby Brooke Herrera
Keyword(s):  
Positive Sample ◽  
Diagnostic Efficiency ◽  
Rt Pcr ◽  
Middle Income ◽  
Pooled Testing ◽  
Middle Income Countries ◽  
Pooling Strategy ◽  
Polymerase Chain ◽  
Antigen Tests ◽  
Antigen Testing

While molecular assays, such as reverse-transcription polymerase chain reaction (RT-PCR), have been widely used throughout the coronavirus disease 2019 (COVID-19) pandemic, the technique is costly and resource intensive. As a means to reduce costs and increase diagnostic efficiency, pooled testing using RT-PCR has been implemented. However, pooling samples for antigen testing has not been evaluated. Here, we propose a proof-of-concept pooling strategy for antigen testing that would significantly expand SARS-CoV-2 surveillance, especially for low-to-middle income countries, schools, and workplaces. Our laboratory-based testing demonstrates that combining of up to 20 nasal swab specimens per pool can expand surveillance with antigen tests, even if a pool contains only one positive sample.

Characterization of a cDNA for Rhesus Monkey Protein C Inhibitor – Evidence for N-Terminal Involvement in Heparin Stimulation

1995 ◽  
Vol 74 (04) ◽  
pp. 1079-1087 ◽  
Author(s):  
Klaus-P Radtke ◽  
José A Fernández ◽  
Bruno O Villoutreix ◽  
Judith S Greengard ◽  
John H Griffin
Keyword(s):  
Rhesus Monkey ◽  
Protein C ◽  
Activated Protein C ◽  
Pcr Amplification ◽  
Amino Acid Sequences ◽  
Heparin Binding ◽  
Reactive Center ◽  
Protein C Inhibitor ◽  
Polymerase Chain

SummarycDNAs for protein C inhibitor (PCI) were cloned from human and rhesus monkey 1 liver RNAs by reverse transcription and polymerase chain reaction (PCR) amplification. Sequencing showed that rhesus monkey and human PCI cDNAs were 93% identical. Predicted amino acid sequences differed at 26 of 387 residues. Pour of these differences (T352M, N359S, R362K, L3631) were in the reactive center loop that is important for inhibitory specificity, and two were in the N-terminal helix (M8T, E13K) that is implicated in glycosaminoglycan binding. PCI in human or rhesus monkey plasma showed comparable inhibitory activity towards human activated protein C in the presence of 10 U/ml heparin. However, maximal acceleration of the inhibition of activated protein C required 5-fold lower heparin concentration for rhesus monkey than for human plasma, consistent with the interpretation that the additional positive charge (E13K) in a putative-heparin binding region increased the affinity for heparin.

Surveillance

2018 ◽  
Author(s):  
Rebecca Sanders
Keyword(s):  
Data Mining ◽  
Cold War ◽  
National Security ◽  
Bush Administration ◽  
The United States ◽  
Search And Seizure ◽  
National Security Agency ◽  
Patriot Act ◽  
The Cold War ◽  
Mass Surveillance

This chapter explores shifting patterns of intelligence surveillance in the United States. The Fourth Amendment protects Americans from unreasonable search and seizure without a warrant, but foreign spying is subject to few constraints. During the Cold War, surveillance power was abused for political purposes. Operating in a culture of secrecy, American intelligence agencies engaged in extensive illegal domestic spying. The intelligence scandals of the 1970s revealed these abuses, prompting new laws, notably the Foreign Intelligence Surveillance Act. Fearing further recrimination, the national security establishment increasingly demanded legal cover. After 9/11, Congress expanded lawful surveillance powers with the PATRIOT Act. Meanwhile, the Bush administration directed the National Security Agency to conduct warrantless domestic wiretapping. To justify this program, officials sought to redefine unconstrained foreign surveillance to subsume previously protected communications. The Obama administration continued to authorize mass surveillance and data mining programs and legally rationalize bulk collection of Americans’ data.

scholarly journals DMSO Improves the Ski-Slope Effect in Direct PCR

2021 ◽  
Vol 11 (4) ◽  
pp. 1943
Author(s):  
Joo-Young Kim ◽  
Ju Yeon Jung ◽  
Da-Hye Kim ◽  
Seohyun Moon ◽  
Won-Hae Lee ◽  
...  
Keyword(s):  
Dna Sequences ◽  
Pcr Amplification ◽  
Analytical Techniques ◽  
Direct Pcr ◽  
Dna Profile ◽  
Novel Technologies ◽  
Specific Amplification ◽  
Polymerase Chain ◽  
Dna Profiles

Analytical techniques such as DNA profiling are widely used in various fields, including forensic science, and novel technologies such as direct polymerase chain reaction (PCR) amplification are continuously being developed in order to acquire DNA profiles efficiently. However, non-specific amplification may occur depending on the quality of the crime scene evidence and amplification methods employed. In particular, the ski-slope effect observed in direct PCR amplification has led to inaccurate interpretations of the DNA profile results. In this study, we aimed to reduce the ski-slope effect by using dimethyl sulfoxide (DMSO) in direct PCR. We confirmed that DMSO (3.75%, v/v) increased the amplification yield of large-sized DNA sequences more than that of small-sized ones. Using 50 Korean buccal samples, we further demonstrated that DMSO reduced the ski-slope effect in direct PCR. These results suggest that the experimental method developed in this study is suitable for direct PCR and may help to successfully obtain DNA profiles from various types of evidence at crime scenes.

scholarly journals 425. The Utility of Paired Upper and Lower COVID-19 Sampling in Patients with Artificial Airways

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S279-S279
Author(s):  
Eimear Kitt ◽  
Julia S Sammons ◽  
Kathleen Chiotos ◽  
Susan E Coffin ◽  
Susan E Coffin ◽  
...  
Keyword(s):  
Respiratory Tract ◽  
Lower Respiratory Tract ◽  
Diagnostic Testing ◽  
Cross Sectional Study ◽  
Upper Respiratory Tract ◽  
Cross Sectional ◽  
Mechanically Ventilated ◽  
Paired Samples ◽  
Control And Prevention ◽  
Polymerase Chain

Abstract Background The Centers for Disease Control and Prevention (CDC) recommends upper respiratory tract (URT) polymerase chain reaction (PCR) testing as the initial diagnostic test for Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2). Lower respiratory tract (LRT) testing for patients requiring mechanical ventilation is also recommended. The goal of this study was to evaluate concordance between paired URT and LRT specimens in children undergoing pre-admission/procedure screening or diagnostic testing. We hypothesized that < 10% of paired tests would have discordant results. Methods Single center cross-sectional study including children with artificial airways who had paired URT and LRT SARS-CoV-2 PCR testing between 4/1/2020 and 6/8/2020. URT specimens included nasopharyngeal (NP) swabs and aspirates. LRT specimens included tracheal aspirates and bronchoalveolar lavages. URT and LRT specimens were classified as paired if the two specimens were collected within 24 hours. Artificial airways included tracheostomies and endotracheal tubes. Tests were classified as diagnostic versus screening based on the indication selected in the order. Results 102 paired specimens were obtained during the study period. Fifty-nine were performed for screening and 43 were performed for diagnosis of suspected SARS-CoV-2. Overall, 94 specimens (92%) were concordant, including 89 negative from both sources and 5 positive from both sources. Eight specimens (8%) were discordant, all of which were positive from the URT and negative from the LRT (Figure 1). Among patients undergoing screening, 3 of 4 positive tests were discordant and among symptomatic patients, 5 of 9 positive tests were discordant. There were no instances of a positive LRT specimen with a negative URT specimen. Figure 1. Performance of upper and lower respiratory tract SARS-CoV-2 PCR testing in children with artificial airways Conclusion Overall, most paired samples from the URT and LRT yielded concordant results with no pairs positive from the LRT and negative from the URT. These data support the CDC recommendation that URT specimens are the preferred initial SARS-CoV-2 test, while LRT specimens should be collected only from mechanically ventilated with suspected SARS-CoV-2. Disclosures All Authors: No reported disclosures

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