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 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 Semi-Quantitative, Duplexed qPCR Assay for the Detection of Leishmania spp. Using Bisulphite Conversion Technology

2019 ◽  
Vol 4 (4) ◽  
pp. 135 ◽  
Author(s):  
Ineka Gow ◽  
Douglas Millar ◽  
John Ellis ◽  
John Melki ◽  
Damien Stark
Keyword(s):  
Limit Of Detection ◽  
Quantitative Polymerase Chain Reaction ◽  
World Health ◽  
Clinical Samples ◽  
Acid Extraction ◽  
Analytical Sensitivity ◽  
Internal Transcribed Spacer Region ◽  
Leishmania Spp ◽  
Sensitivity Data ◽  
Conversion Technology

Leishmaniasis is caused by the flagellated protozoan Leishmania, and is a neglected tropical disease (NTD), as defined by the World Health Organisation (WHO). Bisulphite conversion technology converts all genomic material to a simplified form during the lysis step of the nucleic acid extraction process, and increases the efficiency of multiplex quantitative polymerase chain reaction (qPCR) reactions. Through utilization of qPCR real-time probes, in conjunction with bisulphite conversion, a new duplex assay targeting the 18S rDNA gene region was designed to detect all Leishmania species. The assay was validated against previously extracted DNA, from seven quantitated DNA and cell standards for pan-Leishmania analytical sensitivity data, and 67 cutaneous clinical samples for cutaneous clinical sensitivity data. Specificity was evaluated by testing 76 negative clinical samples and 43 bacterial, viral, protozoan and fungal species. The assay was also trialed in a side-by-side experiment against a conventional PCR (cPCR), based on the Internal transcribed spacer region 1 (ITS1 region). Ninety-seven percent of specimens from patients that previously tested positive for Leishmania were positive for Leishmania spp. with the bisulphite conversion assay, and a limit of detection (LOD) of 10 copies per PCR was achieved, while the LOD of the ITS1 methodology was 10 cells/1000 genomic copies per PCR. This method of rapid, accurate and simple detection of Leishmania can lead to improved diagnosis, treatment and public health outcomes.

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 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 PERFORMANCE CHARACTERISTICS OF A FRET-BASED IMMUNOASSAY FOR QUANTITATION OF INFLIXIMAB ON A POINT-OF-CARE INSTRUMENT SYSTEM

2021 ◽  
Vol 27 (Supplement_1) ◽  
pp. S57-S57
Author(s):  
Edgar Ong ◽  
Ruo Huang ◽  
Richard Kirkland ◽  
Michael Hale ◽  
Larry Mimms
Keyword(s):  
Whole Blood ◽  
Limit Of Detection ◽  
Point Of Care ◽  
Quantitative Detection ◽  
Therapeutic Drug ◽  
Analytical Sensitivity ◽  
Sample Type ◽  
Hook Effect ◽  
Limit Of Quantitation ◽  
Assay Precision

Abstract Introduction A fast (<5 min), time-resolved fluorescence resonance energy transfer (FRET)-based immunoassay was developed for the quantitative detection of infliximab (IFX) and biosimilars for use in therapeutic drug monitoring using only 20 µL of fingerstick whole blood or serum at the point-of-care. The Procise IFX assay and ProciseDx analyzer are CE-marked. Studies were performed to characterize analytical performance of the Procise IFX assay on the ProciseDx analyzer. Methods Analytical testing was performed by spiking known amounts of IFX into negative serum and whole blood specimens. Analytical sensitivity was determined using limiting concentrations of IFX. Linearity was determined by testing IFX across the assay range. Hook effect was assessed at IFX concentrations beyond levels expected to be found within a patient. Testing of assay precision, cross-reactivity and potential interfering substances, and biosimilars was performed. The Procise IFX assay was also compared head-to-head with another CE-marked assay: LISA-TRACKER infliximab ELISA test (Theradiag, France). The accuracy of the Procise IFX assay is established through calibrators and controls traceable to the WHO 1st International Standard for Infliximab (NIBSC code: 16/170). Results The Procise IFX assay shows a Limit of Blank, Limit of Detection, and Lower Limit of Quantitation (LLoQ) of 0.1, 0.2, and 1.1 µg/mL in serum and 0.6, 1.1, and 1.7 µg/mL in whole blood, respectively. The linear assay range was determined to be 1.7 to 77.2 µg/mL in serum and whole blood. No hook effect was observed at an IFX concentration of 200 µg/mL as the value reported as “>ULoQ”. Assay precision testing across 20 days with multiple runs and reagent lots showed an intra-assay coefficient of variation (CV) of 2.7%, an inter-assay CV of <2%, and a total CV of 3.4%. The presence of potentially interfering/cross-reacting substances showed minimal impact on assay specificity with %bias within ±8% of control. Testing of biosimilars (infliximab-dyyb and infliximab-abda) showed good recovery. A good correlation to the Theradiag infliximab ELISA was obtained for both serum (slope=1.01; r=0.99) and whole blood (slope=1.01; r=0.98) samples (Figure 1). Conclusion Results indicate that the Procise IFX assay is sensitive, specific, and precise yielding results within 5 minutes from both whole blood and serum without the operator needing to specify sample type. Additionally, it shows very good correlation to a comparator assay that takes several hours and sample manipulation to yield results. This makes the Procise IFX assay ideal for obtaining fast and accurate IFX quantitation, thus allowing for immediate drug level dosing decisions to be made by the physician during patient treatment.

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 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 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 Analytical sensibility and specificity of two RT-qPCR protocols for SARS-CoV-2 detection performed in an automated workflow

2020 ◽  
Author(s):  
Gustavo Barcelos Barra ◽  
Ticiane Henriques Santa Rita ◽  
Pedro Góes Mesquita ◽  
Rafael Henriques Jácomo ◽  
Lídia Freire Abdalla Nery
Keyword(s):  
Laboratory Diagnosis ◽  
Public Health Emergency ◽  
World Health ◽  
Analytical Sensitivity ◽  
Rna Targets ◽  
Qualitative Detection ◽  
The World ◽  
Confirmatory Assay ◽  
Automated Platform ◽  
Health Organization

AbstractThe World Health Organization declared that COVID-19 outbreak constituted a Public Health Emergency of International Concern and the development of reliable laboratory diagnosis of SARS-CoV-2 became mandatory to identify, isolate and provide optimized care for patients early. RT-qPCR testing of respiratory secretions is routinely used to detect causative viruses in acute respiratory infection. RT-qPCR in-house protocols to detect the SARS-CoV-2 have been described. Validations of these protocols are considered a key knowledge gap for COVID-19, especially if executed in a high throughput format. Here, we investigate the analytical sensitivity and specificity of two interim RT-qPCR protocols for the qualitative detection of SARS-CoV-2 executed in a fully automated platform. Under our conditions, the N1 and RdRP (modified) showed the highest analytical sensitivity for their RNA targets. E assay, in its original concentration, was considered a tertiary confirmatory assay. Taken together, N1, RdRP (optimized) and E presented appropriated analytical sensibility and specificity in our automated RT-qPCR workflow for COVID-19 virus, E being at least 4-fold less sensitive than the others. This study highlights the importance of local validation of in-house assays before its availability to the population. The use of the synthetic RT-qPCR target to investigate novel assays diagnostic parameters in automated workflows is a quick, simple effective way to be prepared for upcoming threats. The proposed assay detected the fisrt SARS-CoV-2 infection in Brazilian Central-West.

Sign in / Sign up

Export Citation Format

Share Document