scholarly journals A SARS-CoV-2 coronavirus nucleocapsid protein antigen-detecting lateral flow assay

PLoS ONE ◽  
2021 ◽  
Vol 16 (11) ◽  
pp. e0258819
Author(s):  
Benjamin D. Grant ◽  
Caitlin E. Anderson ◽  
Luis F. Alonzo ◽  
Spencer H. Garing ◽  
John R. Williford ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Point Of Care ◽  
Lateral Flow ◽  
World Health ◽  
Analytical Sensitivity ◽  
Rapid Diagnostics ◽  
Middle Income ◽  
Efficient Detection ◽  
Gamma Irradiated ◽  
Health Organization

Inexpensive, simple, rapid diagnostics are necessary for efficient detection, treatment, and mitigation of COVID-19. Assays for SARS-CoV2 using reverse transcription polymerase chain reaction (RT-PCR) offer good sensitivity and excellent specificity, but are expensive, slowed by transport to centralized testing laboratories, and often unavailable. Antigen-based assays are inexpensive and can be rapidly mass-produced and deployed at point-of-care, with lateral flow assays (LFAs) being the most common format. While various manufacturers have produced commercially available SARS-Cov2 antigen LFAs, access to validated tests remains difficult or cost prohibitive in low-and middle-income countries. Herein, we present a visually read open-access LFA (OA-LFA) using commercially-available antibodies and materials for the detection of SARS-CoV-2. The LFA yielded a Limit of Detection (LOD) of 4 TCID50/swab of gamma irradiated SARS-CoV-2 virus, meeting the acceptable analytical sensitivity outlined by in World Health Organization target product profile. The open-source architecture presented in this manuscript provides a template for manufacturers around the globe to rapidly design a SARS-CoV2 antigen test.

scholarly journals A SARS-CoV-2 Coronavirus Nucleocapsid Protein Antigen-Detecting Lateral Flow Assay

2020 ◽  
Author(s):  
Ben D Grant ◽  
Caitlin E Anderson ◽  
Spencer H Garing ◽  
Luis F Alonzo ◽  
John R Williford ◽  
...  
Keyword(s):  
Nucleocapsid Protein ◽  
Limit Of Detection ◽  
Point Of Care ◽  
Lateral Flow ◽  
Rapid Diagnostics ◽  
Rt Pcr ◽  
Efficient Detection ◽  
Lateral Flow Assays ◽  
Optical Reader ◽  
Polymerase Chain

<p></p><p>Inexpensive, simple, rapid diagnostics are necessary for efficient detection, treatment and mitigation of COVID‑19. Currently, the primary diagnostic tool being utilized is reverse transcription polymerase chain reaction (RT-PCR). RT-PCR delivers results with good sensitivity and excellent specificity, but is expensive, prone to access challenges and is often slowed by transport to centralized testing laboratories. Antigen-based assays are inexpensive and can be rapidly mass-produced and deployed, with lateral flow assays (LFAs) being the most common inexpensive antigen test. To date, few antigen-detecting LFAs for COVID-19 have been commercialized. Herein, we present an open source LFA using commercially available antibodies and materials for the detection of SARS-CoV-2. Using an optical reader with comparable sensitivity to a visual read, the LFA yielded a Limit of Detection (LOD) of 23 TCID<sub>50</sub>/mL (95% CI of 9.1 to 37 TCID<sub>50</sub>/mL), equivalent to 1.4x10<sup>5</sup> copies/mL (95% CI of 5.5x10<sup>4</sup> to 2.3x10<sup>5</sup> copies/mL) irradiated virus in pooled nasal matrix. This LOD meets the criteria suggested by WHO for diagnosis of acute SARS-CoV-2 infection in a point of care format. A clinical evaluation and further testing is ongoing.</p><p></p>

scholarly journals A SARS-CoV-2 Coronavirus Nucleocapsid Protein Antigen-Detecting Lateral Flow Assay

2020 ◽  
Author(s):  
Ben D Grant ◽  
Caitlin E Anderson ◽  
Spencer H Garing ◽  
Luis F Alonzo ◽  
John R Williford ◽  
...  
Keyword(s):  
Nucleocapsid Protein ◽  
Limit Of Detection ◽  
Point Of Care ◽  
Lateral Flow ◽  
Rapid Diagnostics ◽  
Rt Pcr ◽  
Efficient Detection ◽  
Lateral Flow Assays ◽  
Optical Reader ◽  
Polymerase Chain

<p></p><p>Inexpensive, simple, rapid diagnostics are necessary for efficient detection, treatment and mitigation of COVID‑19. Currently, the primary diagnostic tool being utilized is reverse transcription polymerase chain reaction (RT-PCR). RT-PCR delivers results with good sensitivity and excellent specificity, but is expensive, prone to access challenges and is often slowed by transport to centralized testing laboratories. Antigen-based assays are inexpensive and can be rapidly mass-produced and deployed, with lateral flow assays (LFAs) being the most common inexpensive antigen test. To date, few antigen-detecting LFAs for COVID-19 have been commercialized. Herein, we present an open source LFA using commercially available antibodies and materials for the detection of SARS-CoV-2. Using an optical reader with comparable sensitivity to a visual read, the LFA yielded a Limit of Detection (LOD) of 23 TCID<sub>50</sub>/mL (95% CI of 9.1 to 37 TCID<sub>50</sub>/mL), equivalent to 1.4x10<sup>5</sup> copies/mL (95% CI of 5.5x10<sup>4</sup> to 2.3x10<sup>5</sup> copies/mL) irradiated virus in pooled nasal matrix. This LOD meets the criteria suggested by WHO for diagnosis of acute SARS-CoV-2 infection in a point of care format. A clinical evaluation and further testing is ongoing.</p><p></p>

scholarly journals Analytical evaluation of thirty-two SARS-CoV-2 lateral flow antigen tests demonstrates sensitivity remains with the SARS-CoV-2 Gamma lineage

2021 ◽  
Author(s):  
Konstantina Kontogianni ◽  
Daisy Bengey ◽  
Dominic Wooding ◽  
Kate Buist ◽  
Caitlin Greenland-Bews ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Lateral Flow ◽  
World Health ◽  
Genome Copy ◽  
Copy Numbers ◽  
Alpha Variant ◽  
And Performance ◽  
Antigen Tests ◽  
Health Organization ◽  
Lateral Flow Tests

AbstractThe limit of detection (LOD) of thirty-two antigen lateral flow tests (Ag-RDT) were evaluated with the SARS-CoV-2 Gamma variant. Twenty-eight of thirty-two Ag-RDTs exceeded the World Health Organization criteria of an LOD of 1.0×106 genome copy numbers/ml and performance was equivalent as with the 2020 B.1 lineage and Alpha variant.

scholarly journals A Chelation-Enhanced Fluorescence Assay Using Thiourea Capped Carbonaceous Fluorescent Nanoparticles For As (III) Detection In Water Samples

2021 ◽  
Author(s):  
Susan Mohammadi ◽  
Somayeh Mohammadi ◽  
Abdollah Salimi ◽  
Rezgar Ahmadi
Keyword(s):  
Water Samples ◽  
Limit Of Detection ◽  
Threshold Value ◽  
Water Soluble ◽  
World Health ◽  
Fluorescent Nanoparticles ◽  
Detection Range ◽  
Turn On ◽  
Efficient Detection ◽  
Health Organization

Abstract Herein, we designed a sensitive and selective “Turn-On” fluorescence nanosensor using water-soluble carbonaceous fluorescent nanomaterials (CFNs) functionalized with thiourea (CFNs-thiourea) for efficient detection of trace amounts of arsenic (III) in aqueous samples. The CFNs and CFNs-Thiourea were characterized by transmission electron microscopy (TEM), UV–Visible spectroscopy (UV-vis) and Fourier transformed infrared spectroscopy (FTIR). The emission peak intensity of proposed nanosensor at 425 nm was gradually enhanced on arsenite addition in wide detection range (3.3–828.5 µg L-1) attributed to the binding of arsenite species with sulfur groups of CFNs-thiourea. The limit of detection (LOD) was 0.48 µg L-1 being much lower than the World Health Organization (WHO) recommended threshold value of 10 µg L-1. Furthermore, the as prepared thiourea -CFNs exhibited an superb selectivity for As (III) compared various cations and anions such as; NO3−, NO2−, F−, Ni2+, Fe3+, Cu2+, Ca2+, Mg2+, Zn2+, Fe2+, Hg2+, Pb2+, F-, Cl-, Mn2+, Cr3+, Co2+, Cd2+, Bi3+, Al3+ and As (V) at 100 folds concentration of As (III). The turn on fluorescence nanosensor was successfully exploited for quantification of arsenic in spiked water samples with acceptable efficiencies.

scholarly journals Point-of-Need Disposable ELISA System for COVID-19 Serology Testing

2021 ◽  
Author(s):  
Cody Carrell ◽  
Jeremy Link ◽  
Ilhoon Jang ◽  
James Terry ◽  
Michael Scherman ◽  
...  
Keyword(s):  
Clinical Laboratory ◽  
Point Of Care ◽  
Lateral Flow ◽  
World Health ◽  
Clinical Samples ◽  
Enzyme Linked Immunosorbent Assay ◽  
Elisa System ◽  
Health Organization ◽  
Care Technology ◽  
Serology Testing

A disposable enzyme-linked immunosorbent assay (dELISA) device for ate-home or doctor’s office use was developed to detect SARS-CoV-2 antibodies. Serology testing for SARS-CoV-2 antibodies is currently run using well-plate ELISAs in centralized laboratories. However, the scale of serology testing needed for epidemiological and clinical screening studies will overwhelm existing clinical laboratory resources. Instead, a point-of-need device that can be used at home or in doctor’s offices for COVID-19 serology testing must be developed and is one of four target products prioritized by the World Health Organization. Lateral flow assays are common and easy to use, but lack the sensitivity needed to reliably detect SARS-CoV-2 antibodies in clinical samples. This work describes a disposable ELISA device that is as simple to use as a lateral flow assay, but as sensitive as a well-plate ELISA. The device utilizes capillary-driven flow channels made of transparency films and double-sided adhesive combined with paper pumps to drive flow. The geometry of the channels and storage pads enables automated sequential washing and reagent addition steps with two simple end-user steps. An enzyme label is used to produce a colorimetric signal instead of a nanoparticle label in order to amplify signal and increase sensitivity, while the integrated washing steps decrease false positives and increase reproducibility. Naked-eye detection can be used for qualitative results or a smartphone camera for quantitative analysis. The device can detect antibodies at 2.8 ng/mL from whole blood, which was very close the concentration of detectable target in a well-plate ELISA (1.2 ng/mL). In this study the dELISA system was used to detect SARS-CoV-2 antibodies, but we believe that the device represents a fundamental step forward in point-of-care technology that will enable sensitive detection of many other analytes outside of a centralized laboratory.

scholarly journals Limit of detection in different matrices of nineteen commercially available rapid antigen tests for the detection of SARS-CoV-2

2021 ◽  
Author(s):  
Ana I. Cubas-Atienzar ◽  
Konstantina Kontogianni ◽  
Thomas Edwards ◽  
Dominic Wooding ◽  
Kate Buist ◽  
...  
Keyword(s):  
Culture Supernatant ◽  
Limit Of Detection ◽  
Culture Media ◽  
Performance Criteria ◽  
World Health ◽  
Analytical Sensitivity ◽  
Sample Type ◽  
Sensitivity Data ◽  
Antigen Tests ◽  
Health Organization

AbstractIn the context of the coronavirus disease 2019 (COVID-19) pandemic there has been an increase of the use of antigen-detection rapid diagnostic tests (Ag-RDT). The performance of Ag-RDT vary greatly between manufacturers and evaluating their analytical limit of detection (LOD) has become high priority. Here we describe a manufacturer-independent evaluation of the LOD of 19 marketed Ag-RDT using live SARS-CoV-2 spiked in different matrices: direct culture supernatant, a dry swab, and a swab in Amies. Additionally, the LOD using dry swab was investigated after 7 days’ storage at −80°C of the SARS-CoV-2 serial dilutions. An LOD of ≈ 5.0 × 102 pfu/ml (1.0 × 106 genome copies/ml) in culture media is defined as acceptable by the World Health Organization. Fourteen of nineteen Ag-RDTs (ActiveXpress, Espline, Excalibur, Innova, Joysbio, Mologic, NowCheck, Orient, PanBio, RespiStrip, Roche, Standard-F, Standard-Q and Sure-Status) exceeded this performance criteria using direct culture supernatant applied to the Ag-RDT. Six Ag-RDT were not compatible with Amies media and a decreased sensitivity of 2 to 20-fold was observed for eleven tests on the stored dilutions at −80°C for 7 days. Here, we provide analytical sensitivity data to guide appropriate test and sample type selection for use and for future Ag-RDT evaluations.

scholarly journals Development and Evaluation of Europium-Based Quantitative Lateral Flow Immunoassay for the Chronic Kidney Disease Marker Cystatin-C

2021 ◽  
Author(s):  
SATHEESH NATARAJAN ◽  
Ebru saatci
Keyword(s):  
Chronic Kidney Disease ◽  
Kidney Disease ◽  
Cystatin C ◽  
Limit Of Detection ◽  
Point Of Care ◽  
Lateral Flow ◽  
Fluorescence Measurement ◽  
Analytical Sensitivity ◽  
Linear Calibration ◽  
Time Resolved

Abstract This study aimed to establish a Europium label time-resolved fluorescence immunoassay (TRFIA) to detect the chronic kidney disease (CKD) biomarker Cystatin-C. Some Cystatin-c immunoassays are sensitive, accurate, and available for clinical application, but they are expensive and time-consuming procedures. Also, conventional organic dye-based fluorescence lateral flow assay showed more background fluorescence interference and low analytical sensitivity. So this Europium-based sandwich immunoassay was developed to detect the concentration of cystatin-c in a urine sample with captured anti-cystatin-c antibodies immobilized on nitrocellulose membrane and then bonded with detection anti-cystatin-c labelled with CM-EU, followed by fluorescence measurement using time-resolved fluorometry in 15 minutes. The performance of this TRFIA was evaluated using the clinical urine serum and compared with the ELISA assays. The linear calibration range was 0.015-32 µg/ml, and the limit of detection (LOD) quantified was 0.0001µg/ml. This current work has improved the LOD of our previous work from 0.013µg/ml to 0.001µg/ml. These results indicated that the CM-EU nanoparticle-based LFIA is rapid, more sensitive, reliable, and reproducible for point-of-care testing of Cys-C concentrations in urine

scholarly journals Limit of detection in different matrices of nineteen commercially available rapid antigen tests for the detection of SARS-CoV-2

2021 ◽  
Author(s):  
Konstantina Kontogianni ◽  
Thomas Edwards ◽  
Dominic Wooding ◽  
Kate Buist ◽  
Caitlin R. Thompson ◽  
...  
Keyword(s):  
Culture Supernatant ◽  
Limit Of Detection ◽  
Culture Media ◽  
Performance Criteria ◽  
World Health ◽  
Analytical Sensitivity ◽  
Sample Type ◽  
Sensitivity Data ◽  
Antigen Tests ◽  
Health Organization

Abstract In the context of the coronavirus disease 2019 (COVID-19) pandemic there has been an increase of the use of antigen-detection rapid diagnostic tests (Ag-RDT). The performance of Ag-RDT vary greatly between manufacturers and evaluating their analytical limit of detection (LOD) has become high priority. Here we describe a manufacturer-independent evaluation of the LOD of 19 marketed Ag-RDT using live SARS-CoV-2 spiked in different matrices: direct culture supernatant, a dry swab, and a swab in Amies. Additionally, the LOD using dry swab was investigated after 7 days’ storage at -80°C of the SARS-CoV-2 serial dilutions. An LOD of ≈ 5.0 x 102 pfu/ml (1.0 x 106 genome copies/ml) in culture media is defined as acceptable by the World Health Organization. Fourteen of nineteen Ag-RDTs (ActiveXpress, Espline, Excalibur, Innova, Joysbio, Mologic, NowCheck, Orient, PanBio, RespiStrip, Roche, Standard-F, Standard-Q and Sure-Status) exceeded this performance criteria using direct culture supernatant applied to the Ag-RDT. Six Ag-RDT were not compatible with Amies media and a decreased sensitivity of 2 to 20-fold was observed for eleven tests on the stored dilutions at -80°C for 7 days. Here, we provide analytical sensitivity data to guide appropriate test and sample type selection for use and for future Ag-RDT evaluations. 201/200

scholarly journals Limit of detection in different matrices of 19 commercially available rapid antigen tests for the detection of SARS-CoV-2

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ana I. Cubas-Atienzar ◽  
Konstantina Kontogianni ◽  
Thomas Edwards ◽  
Dominic Wooding ◽  
Kate Buist ◽  
...  
Keyword(s):  
Culture Supernatant ◽  
Limit Of Detection ◽  
Culture Media ◽  
Performance Criteria ◽  
World Health ◽  
Analytical Sensitivity ◽  
Sample Type ◽  
Sensitivity Data ◽  
Antigen Tests ◽  
Health Organization

AbstractIn the context of the coronavirus disease 2019 (COVID-19) pandemic there has been an increase of the use of antigen-detection rapid diagnostic tests (Ag-RDT). The performance of Ag-RDT vary greatly between manufacturers and evaluating their analytical limit of detection (LOD) has become high priority. Here we describe a manufacturer-independent evaluation of the LOD of 19 marketed Ag-RDT using live SARS-CoV-2 spiked in different matrices: direct culture supernatant, a dry swab, and a swab in Amies. Additionally, the LOD using dry swab was investigated after 7 days’ storage at − 80 °C of the SARS-CoV-2 serial dilutions. An LOD of ≈ 5.0 × 102 pfu/ml (1.0 × 106 genome copies/ml) in culture media is defined as acceptable by the World Health Organization. Fourteen of 19 Ag-RDTs (ActiveXpress, Espline, Excalibur, Innova, Joysbio, Mologic, NowCheck, Orient, PanBio, RespiStrip, Roche, Standard-F, Standard-Q and Sure-Status) exceeded this performance criteria using direct culture supernatant applied to the Ag-RDT. Six Ag-RDT were not compatible with Amies media and a decreased sensitivity of 2 to 20-fold was observed for eleven tests on the stored dilutions at − 80 °C for 7 days. Here, we provide analytical sensitivity data to guide appropriate test and sample type selection for use and for future Ag-RDT evaluations.

scholarly journals Point-of-Need Disposable ELISA System for COVID-19 Serology Testing

2020 ◽  
Author(s):  
Cody Carrell ◽  
Jeremy Link ◽  
Ilhoon Jang ◽  
James Terry ◽  
Michael Scherman ◽  
...  
Keyword(s):  
Clinical Laboratory ◽  
Point Of Care ◽  
Lateral Flow ◽  
World Health ◽  
Clinical Samples ◽  
Enzyme Linked Immunosorbent Assay ◽  
Elisa System ◽  
Health Organization ◽  
Care Technology ◽  
Serology Testing

A disposable enzyme-linked immunosorbent assay (dELISA) device for ate-home or doctor’s office use was developed to detect SARS-CoV-2 antibodies. Serology testing for SARS-CoV-2 antibodies is currently run using well-plate ELISAs in centralized laboratories. However, the scale of serology testing needed for epidemiological and clinical screening studies will overwhelm existing clinical laboratory resources. Instead, a point-of-need device that can be used at home or in doctor’s offices for COVID-19 serology testing must be developed and is one of four target products prioritized by the World Health Organization. Lateral flow assays are common and easy to use, but lack the sensitivity needed to reliably detect SARS-CoV-2 antibodies in clinical samples. This work describes a disposable ELISA device that is as simple to use as a lateral flow assay, but as sensitive as a well-plate ELISA. The device utilizes capillary-driven flow channels made of transparency films and double-sided adhesive combined with paper pumps to drive flow. The geometry of the channels and storage pads enables automated sequential washing and reagent addition steps with two simple end-user steps. An enzyme label is used to produce a colorimetric signal instead of a nanoparticle label in order to amplify signal and increase sensitivity, while the integrated washing steps decrease false positives and increase reproducibility. Naked-eye detection can be used for qualitative results or a smartphone camera for quantitative analysis. The device can detect antibodies at 2.8 ng/mL from whole blood, which was very close the concentration of detectable target in a well-plate ELISA (1.2 ng/mL). In this study the dELISA system was used to detect SARS-CoV-2 antibodies, but we believe that the device represents a fundamental step forward in point-of-care technology that will enable sensitive detection of many other analytes outside of a centralized laboratory.

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