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 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 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 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.

Characterizing the effectiveness of COVID-19 mitigation measures: A data-centric approach (Preprint)

2020 ◽  
Author(s):  
Lukman Olagoke ◽  
Ahmet E. Topcu
Keyword(s):  
Control Measure ◽  
Control Measures ◽  
World Health ◽  
Mitigation Measures ◽  
Effective Control ◽  
The World ◽  
Decision Making Processes ◽  
And Performance ◽  
Health Organization ◽  
The Impact

BACKGROUND COVID-19 represents a serious threat to both national health and economic systems. To curb this pandemic, the World Health Organization (WHO) issued a series of COVID-19 public safety guidelines. Different countries around the world initiated different measures in line with the WHO guidelines to mitigate and investigate the spread of COVID-19 in their territories. OBJECTIVE The aim of this paper is to quantitatively evaluate the effectiveness of these control measures using a data-centric approach. METHODS We begin with a simple text analysis of coronavirus-related articles and show that reports on similar outbreaks in the past strongly proposed similar control measures. This reaffirms the fact that these control measures are in order. Subsequently, we propose a simple performance statistic that quantifies general performance and performance under the different measures that were initiated. A density based clustering of based on performance statistic was carried out to group countries based on performance. RESULTS The performance statistic helps evaluate quantitatively the impact of COVID-19 control measures. Countries tend show variability in performance under different control measures. The performance statistic has negative correlation with cases of death which is a useful characteristics for COVID-19 control measure performance analysis. A web-based time-line visualization that enables comparison of performances and cases across continents and subregions is presented. CONCLUSIONS The performance metric is relevant for the analysis of the impact of COVID-19 control measures. This can help caregivers and policymakers identify effective control measures and reduce cases of death due to COVID-19. The interactive web visualizer provides easily digested and quick feedback to augment decision-making processes in the COVID-19 response measures evaluation. CLINICALTRIAL Not Applicable

scholarly journals Water Quality of the Trstionica River (Bosnia and Herzegovina)

2020 ◽  
Vol 69 (7-8) ◽  
pp. 371-376
Author(s):  
Šuhreta Delibašić ◽  
Jasna Huremović ◽  
Sabina Žero ◽  
Sabina Gojak-Salimović
Keyword(s):  
Water Quality ◽  
Bosnia And Herzegovina ◽  
Limit Of Detection ◽  
Weather Conditions ◽  
Ion Exchange Resin ◽  
World Health ◽  
Mean Values ◽  
Significant Difference ◽  
Health Organization

The present study was conducted to investigate the water quality of the Trstionica River, Bosnia and Herzegovina. The physicochemical properties (temperature, pH, conductivity, total solids after evaporation at 105 °C), content of metals (calcium (Ca), cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), magnesium (Mg), manganese (Mn), sodium (Na), nickel (Ni), lead (Pb) and zinc (Zn)), and anions (chloride (Cl–), and phosphate (PO43–)) were determined in water samples collected at seven locations during two sampling periods: unstable weather conditions (precipitation), and stable weather conditions (without precipitation). There was a significant difference in the content of individual parameters in the river water depending on the sampling time. For determination of metals concentrations, which were below the limit of detection, a preconcentration method using an ion-exchange resin was applied. The metals concentrations during the rainy day were in the order Ca > Mg > Na > Fe > Cu > Zn > Pb > Mn with mean values of 343, 6.03, 1.94, 0.18, 0.20, 0.03, 0.02, 0.01 mg dm–3, respectively, and during stable weather conditions: Ca > Mg > Na > Cu > Fe > Mn > Zn with mean values of 288, 7.62, 2.38, 0.11, 0.10, 0.01, 0.01 mg dm–3, respectively. Cd, Cr, and Ni concentrations were below limit of detection in both cases. Obtained values were compared with World Health Organization (WHO) regulations. The results showed that the Trstionica River in the investigated part of the stream meets most of the parameters required by the regulations. The correlation between analysed parameters was assessed, as well. Based on the calculated water quality index values, the water of Trstionica River falls into the category of excellent water.

scholarly journals Walkable Urban Environments: An Ergonomic Approach of Evaluation

2019 ◽  
Author(s):  
Letizia Appolloni ◽  
Alberto Giretti ◽  
Daniela D'Alessandro
Keyword(s):  
Bayesian Network ◽  
Urban Space ◽  
Urban Environments ◽  
World Health ◽  
Related Factors ◽  
Average Value ◽  
And Performance ◽  
Health Organization ◽  
The Relationship ◽  
Space Method

Background: The World Health Organization (WHO) stresses the need to create active environments, able to promote physical activity of people, according to their ability. Objective; This paper describes a new tool curried out to meaasure the relationship between the characteristics of urban space and its salutogenicity, intended as its ability to address population toward healthy lifestyles. Salutogenity has been read in terms of ergonomics of urban space. Method: The tool includes a set of 67 parameters, classified in needs, requirements and performance. It focuses on three requirements: usability, wellbeing and safety. The related performances are measured by a set of 29 indicators, divided in 5 categories (natural elements, built environment, mobility, urban furniture and perceived environment). To calibrate the tool, it was applied to 10 neighborhoods of Rieti city. To take into account the relationship between the variables, a causal network (Bayesian network) was applied. Findings: The average value of ergonomics of Rieti city, obtained applying the discrete bayesian model is 44.25%. Using the network, it is evident that by intervening on one node, the information requested expands to all the other nodes to which it is connected directly or indirectly, showing all the possible related factors. Conclusions: By using the tool and the discrete bayesian network it was possible to focus on the realities requiring analysis and to indicate the areas where the first interventions would be useful to increase the value of the analyzed nodes and, consequently, to improve the urban salutogenicity.

scholarly journals Noncompetitive Chromogenic Lateral-Flow Immunoassay for Simultaneous Detection of Microcystins and Nodularin

Biosensors ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 79 ◽  
Author(s):  
Sultana Akter ◽  
Teemu Kustila ◽  
Janne Leivo ◽  
Gangatharan Muralitharan ◽  
Markus Vehniäinen ◽  
...  
Keyword(s):  
Water Quality ◽  
Simultaneous Detection ◽  
Antibody Fragment ◽  
Water Quality Monitoring ◽  
Lateral Flow ◽  
Cyanobacterial Blooms ◽  
World Health ◽  
Lateral Flow Immunoassay ◽  
Guideline Value ◽  
Health Organization

Cyanobacterial blooms cause local and global health issues by contaminating surface waters. Microcystins and nodularins are cyclic cyanobacterial peptide toxins comprising numerous natural variants. Most of them are potent hepatotoxins, tumor promoters, and at least microcystin-LR is possibly carcinogenic. In drinking water, the World Health Organization (WHO) recommended the provisional guideline value of 1 µg/L for microcystin-LR. For water used for recreational activity, the guidance values for microcystin concentration varies mostly between 4–25 µg/L in different countries. Current immunoassays or lateral flow strips for microcystin/nodularin are based on indirect competitive method, which are generally more prone to sample interference and sometimes hard to interpret compared to two-site immunoassays. Simple, sensitive, and easy to interpret user-friendly methods for first line screening of microcystin/nodularin near water sources are needed for assessment of water quality and safety. We describe the development of a two-site sandwich format lateral-flow assay for the rapid detection of microcystins and nodularin-R. A unique antibody fragment capable of broadly recognizing immunocomplexes consisting of a capture antibody bound to microcystins/nodularin-R was used to develop the simple lateral flow immunoassay. The assay can visually detect the major hepatotoxins (microcystin-LR, -dmLR, -RR, -dmRR, -YR, -LY, -LF -LW, and nodularin-R) at and below the concentration of 4 µg/L. The signal is directly proportional to the concentration of the respective toxin, and the use of alkaline phosphatase activity offers a cost efficient alternative by eliminating the need of toxin conjugates or other labeling system. The easy to interpret assay has the potential to serve as a microcystins/nodularin screening tool for those involved in water quality monitoring such as municipal authorities, researchers, as well as general public concerned of bathing water quality.

scholarly journals Guidance for Studies Evaluating the Accuracy of Rapid Tuberculosis Drug-Susceptibility Tests

2019 ◽  
Vol 220 (Supplement_3) ◽  
pp. S126-S135 ◽  
Author(s):  
Sophia B Georghiou ◽  
Samuel G Schumacher ◽  
Timothy C Rodwell ◽  
Rebecca E Colman ◽  
Paolo Miotto ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Evaluation Studies ◽  
Drug Susceptibility ◽  
Drug Susceptibility Testing ◽  
World Health ◽  
Policy Recommendations ◽  
Operational Characteristics ◽  
Susceptibility Tests ◽  
Health Organization ◽  
Intended Use

Abstract The development and implementation of rapid molecular diagnostics for tuberculosis (TB) drug-susceptibility testing is critical to inform treatment of patients and to prevent the emergence and spread of resistance. Optimal trial planning for existing tests and those in development will be critical to rapidly gather the evidence necessary to inform World Health Organization review and to support potential policy recommendations. The evidence necessary includes an assessment of the performance for TB and resistance detection as well as an assessment of the operational characteristics of these platforms. The performance assessment should include analytical studies to confirm the limit of detection and assay ability to detect mutations conferring resistance across globally representative strains. The analytical evaluation is typically followed by multisite clinical evaluation studies to confirm diagnostic performance in sites and populations of intended use. This paper summarizes the considerations for the design of these analytical and clinical studies.

scholarly journals Design of Multiplex Lateral Flow Tests: A Case Study for Simultaneous Detection of Three Antibiotics

2019 ◽  
Author(s):  
Anastasiya V. Bartosh ◽  
Dmitriy V. Sotnikov ◽  
Olga D. Hendrickson ◽  
Anatoly V. Zherdev ◽  
Boris B. Dzantiev
Keyword(s):  
Limit Of Detection ◽  
Simultaneous Detection ◽  
Optimal Location ◽  
Lateral Flow ◽  
Lateral Flow Assay ◽  
Immunochromatographic Test ◽  
Equilibrium Conditions ◽  
Lateral Flow Tests ◽  
The Impact

The presented study is focused on the impact of binding zones locations at immunochromatographic test strips into analytical parameters of multiplex lateral flow assay. Due to non-equilibrium conditions for such assays the duration of immune reactions influences significantly on analytical parameters, and the integration of several analytes into one multiplex strip may cause essential decrease of sensitivity. To choose the best location of binding zones, we have tested reactants for immunochromatographic assays of lincomycin, chloramphenicol, and tetracycline. The influence of the distance to the binding zones on the intensity of coloration and limit of detection (LOD) was rather different. Basing on the obtained data, the best order of binding zones was chosen. In comparison with non-optimal location the LODs were 5-10 fold improved. The final assay provides LODs 0.4, 0.4 and 1.0 ng/mL for lincomycin, chloramphenicol, and tetracycline, respectively. The proposed approach can be applied for multiassays of other analytes.

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