scholarly journals A SARS-CoV-2 Coronavirus Antigen-Detecting Half-Strip Lateral Flow Assay Towards the Development of Point of Care Tests Using Commercially Available Reagents

2020 ◽  
Author(s):  
Benjamin D. Grant ◽  
Caitlin E. Anderson ◽  
John R Williford ◽  
Luis F. Alonzo ◽  
Veronika A. Glukhova ◽  
...  
Keyword(s):  
Point Of Care ◽  
Diagnostic Testing ◽  
Lateral Flow ◽  
Rt Pcr ◽  
Middle Income ◽  
Efficient Treatment ◽  
Clinical Sensitivity ◽  
Starting Point ◽  
Half Strip ◽  
Implementation Costs

<p>The SARS-CoV-2 pandemic has created an unprecedented need for rapid diagnostic testing to enable the efficient treatment and mitigation of COVID-19. The primary diagnostic tool currently employed is reverse transcription polymerase chain reaction (RT-PCR), which can have good sensitivity and excellent specificity. Unfortunately, implementation costs and logistical problems with reagents during the global SARS-CoV-2 pandemic have hindered its universal on demand adoption. Lateral flow assays (LFAs) represent a class of diagnostic that, if sufficiently clinically sensitive, may fill many of the gaps in the current RT-PCR testing regime, especially in low- and middle-income countries (LMICs). To date, many serology LFAs have been developed, though none meet the performance requirements necessary for diagnostic use cases, primarily due to the relatively long delay between infection and seroconversion. However, based on previously reported results from SARS-CoV-1, antigen-based SARS-CoV-2 assays may have significantly better clinical sensitivity than serology assays. To date, only a very small number of antigen-detecting LFAs have been developed. Development of a half-strip LFA is a useful first step in the development of any LFA format. In this paper we present a half-strip LFA using commercially available antibodies for the detection of SARS-CoV-2. We have tested this LFA in buffer and measured an LOD of 0.62 ng/mL using an optical reader with sensitivity equivalent to a visual read. Further development, including evaluating the appropriate sample matrix, will be required for this assay approach to be made useful in a point of care setting, though this half-strip LFA may serve as a useful starting point for others developing similar tests. </p>

scholarly journals A SARS-CoV-2 Coronavirus Antigen-Detecting Half-Strip Lateral Flow Assay Towards the Development of Point of Care Tests Using Commercially Available Reagents

2020 ◽  
Author(s):  
Benjamin D. Grant ◽  
Caitlin E. Anderson ◽  
John R Williford ◽  
Luis F. Alonzo ◽  
Veronika A. Glukhova ◽  
...  
Keyword(s):  
Point Of Care ◽  
Diagnostic Testing ◽  
Lateral Flow ◽  
Rt Pcr ◽  
Middle Income ◽  
Efficient Treatment ◽  
Clinical Sensitivity ◽  
Starting Point ◽  
Half Strip ◽  
Implementation Costs

<p>The SARS-CoV-2 pandemic has created an unprecedented need for rapid diagnostic testing to enable the efficient treatment and mitigation of COVID-19. The primary diagnostic tool currently employed is reverse transcription polymerase chain reaction (RT-PCR), which can have good sensitivity and excellent specificity. Unfortunately, implementation costs and logistical problems with reagents during the global SARS-CoV-2 pandemic have hindered its universal on demand adoption. Lateral flow assays (LFAs) represent a class of diagnostic that, if sufficiently clinically sensitive, may fill many of the gaps in the current RT-PCR testing regime, especially in low- and middle-income countries (LMICs). To date, many serology LFAs have been developed, though none meet the performance requirements necessary for diagnostic use cases, primarily due to the relatively long delay between infection and seroconversion. However, based on previously reported results from SARS-CoV-1, antigen-based SARS-CoV-2 assays may have significantly better clinical sensitivity than serology assays. To date, only a very small number of antigen-detecting LFAs have been developed. Development of a half-strip LFA is a useful first step in the development of any LFA format. In this paper we present a half-strip LFA using commercially available antibodies for the detection of SARS-CoV-2. We have tested this LFA in buffer and measured an LOD of 0.62 ng/mL using an optical reader with sensitivity equivalent to a visual read. Further development, including evaluating the appropriate sample matrix, will be required for this assay approach to be made useful in a point of care setting, though this half-strip LFA may serve as a useful starting point for others developing similar tests. </p>

Point-Of-Care Clinical Evaluation of the Clungene® SARS-CoV-2 Virus IgG/IgM 15-minute rapid test cassette with the Cobas® Roche RT-PCR platform in patients with or without Covid-19

2021 ◽  
Author(s):  
Fadi Haddad ◽  
Christopher C Lamb ◽  
Ravina Kullar ◽  
George Sakoulas
Keyword(s):  
Symptom Onset ◽  
Serological Test ◽  
Point Of Care ◽  
Diagnostic Testing ◽  
Rapid Test ◽  
Lateral Flow ◽  
Added Value ◽  
Lateral Flow Immunoassay ◽  
Rt Pcr ◽  
Past Infection

Background: Covid-19 remains a pandemic with multiple challenges to confirm patient infectivity: lack of sufficient tests, accurate results, validated quality, and timeliness of results. We hypothesize that a rapid 15-minute Point-Of-Care serological test to evaluate past infection complements diagnostic testing for Covid-19 and significantly enhances testing availability. Method: A three arm observational study at Sharp Healthcare, San Diego, California was conducted using the Clungene® lateral flow immunoassay (LFI) and compared with the Cobas® Roche RT PCR results. Arm 1: Thirty-five (35) subjects with confirmed Covid-19 using RT-PCR were tested twice: prior to 14 days following symptom onset and once between 12 and 70 days. Arm 2: Thirty (30) subjects with confirmed Covid-19 using RT-PCR were tested 12-70 days post symptom onset. Arm 3: Thirty (30) subjects with a negative RT-PCR for Covid-19 were tested 1-10 days following the RT-PCR test date. Results: Specificity of confirmed negative Covid-19 by RT-PCR was 100% (95% CI, 88.4%-100.0%); meaning there was 100% negative positive agreement between the RT-PCR and the Clungene® serological test results. Covid-19 subjects tested prior to day 7 symptom onset were antibody negative. In subjects 7-12 days following symptom onset with a confirmed positive Covid-19 by RT-PCR, the combined sensitivity of IgM and IgG was 58.6% (95% CI, 38.9%-76.5%). In subjects 13-70 days following symptom onset with a confirmed positive Covid-19 by RT-PCR the combined sensitivity of IgM and IgG was 90.5% (95% CI, 80.4%-96.4%). Conclusion: The Clungene® lateral flow immunoassay (LFI) is a useful tool to confirm individuals with an adaptive immune response to SARS-CoV-2 indicating past infection. Providing Point-Of-Care results within 15 minutes without any laboratory instrumentation or specialized software has an added value of increasing test availability to patients who have been symptomatic for more than one week to confirm past infection. Performance characteristics are optimal after 13 days with a sensitivity and specificity of 90% and 100%, respectively.

scholarly journals Clinical validation of a point-of-care antibody test for COVID-19

2020 ◽  
Author(s):  
Monila Patel ◽  
Yogesh Lakhotia ◽  
Sneha Shah ◽  
Nilay Suthar ◽  
Cherry Shah ◽  
...  
Keyword(s):  
Confidence Interval ◽  
Sensitivity And Specificity ◽  
Significant Role ◽  
Point Of Care ◽  
Antibody Test ◽  
Lateral Flow ◽  
Clinical Validation ◽  
Rt Pcr ◽  
Antibody Tests ◽  
Spike Proteins

AbstractThe objective of this study was to evaluate the performance of a lateral flow antibody test for COVID-19, approved for use in India. Although many point-of-care antibody tests are available globally, they have been subjected to limited clinical validation. This has led to suboptimal outcomes in the field, where antibody tests play a significant role in tracking the immunity of individuals and communities. In this study an antibody test, ImmunoQuick that recognizes antibodies to the Nucleocapsid and Spike proteins of SARS CoV-2 was tested in 100 symptomatic patients with a positive or negative diagnosis of COVID-19, based on RT-PCR results. The overall sensitivity of the test was found to be 86.1% (95% CI: 76.4% to 92.8%) and specificity 100% (95% confidence interval: 73.5% to 100%). The sensitivity reached a peak of 95.7% with samples taken 17 days after the onset of symptoms. Overall, the sensitivity and specificity of the test are sufficient for assessing seroprevalence.

scholarly journals Clinical Evaluation of a COVID-19 Antibody Lateral Flow Assay using Point of Care Samples

2020 ◽  
Author(s):  
Won Lee ◽  
Steven Straube ◽  
Ryan Sincic ◽  
Jeanne A. Noble ◽  
Juan Carlos Montoy ◽  
...  
Keyword(s):  
Predictive Value ◽  
Point Of Care ◽  
Acute Infection ◽  
High Specificity ◽  
Lateral Flow ◽  
Lateral Flow Immunoassay ◽  
Onset Date ◽  
Rt Pcr ◽  
Serum Samples ◽  
Antibody Positivity

ABSTRACTIntroductionThe ongoing SARS-CoV-2 pandemic has spurred the development of numerous point of care (PoC) immunoassays. Assessments of performance of available kits are necessary to determine their clinical utility. Previous studies have mostly performed these assessments in a laboratory setting, which raises concerns of translating findings for PoC use. The aim of this study was to assess the performance of a lateral flow immunoassay for the detection of SARS-CoV-2 antibodies using samples collected at PoC.MethodOne lateral flow immunoassay (Humasis® COVID-19 IgG/IgM) was tested. In total, 50 PCR RT-PCR positive and 52 RT-PCR negative samples were collected at PoC. Fifty serum specimens from Dec 2018 to Feb 2019 were used as controls for specificity. Serum samples collected between Dec 2019 to Feb 2020 were used as additional comparators. Clinical data including symptom onset date was collected from patient history and the medical record.ResultsThe overall sensitivity for the kit was 74% (95% CI: 59.7% -85.4%). The sensitivity for IgM and IgG detection >14 days after date of onset was 88% (95% CI: 68.8% -97.5%) and 84% (95% CI: 63.9% – 95.5%), with a negative predictive value (NPV) of 94% for IgM (95% CI: 83.5% - 98.8%) and 93% for IgG (95% CI: 81.8% - 97.9%). The overall specificity was 94% (95% CI: 83.5% - 98.8%). The Immunoglobulin specific specificity was 94% for IgM (95% CI: 83.5% - 98.8%) and 98% for IgG (95% CI: 89.4% - 100.0%), with a positive predictive value (PPV) of 88% for IgM (95% CI: 68.8% - 97.5%) and 95% for IgG (95% CI: 77.2% - 99.9%) respectively for samples collected from patients >14 days after date of onset. Specimen collected during early phase of COVID-19 pandemic (Dec 2019 to Feb 2020) showed 11.8% antibody positivity, and 11.3% of PCR-negative patients demonstrated antibody positivity.DiscussionHumasis® COVID-19 IgG/IgM LFA demonstrates greater than 90% PPV and NPV for samples collected 14 days after the onset of symptoms using samples collected at PoC. While not practical for the diagnosis of acute infection, the use of the lateral flow assays with high specificity may have utility for determining seroprevalence or seroconversion in longitudinal studies.

scholarly journals Comparing the diagnostic accuracy of point-of-care lateral flow antigen testing for SARS-CoV-2 with RT-PCR in primary care (REAP-2)

2021 ◽  
pp. 101011
Author(s):  
Werner Leber ◽  
Oliver Lammel ◽  
Andrea Siebenhofer ◽  
Monika Redlberger-Fritz ◽  
Jasmina Panovska-Griffiths ◽  
...  
Keyword(s):  
Primary Care ◽  
Diagnostic Accuracy ◽  
Point Of Care ◽  
Lateral Flow ◽  
Rt Pcr ◽  
Antigen Testing

scholarly journals Microneedle-based skin patch for blood-free rapid diagnostic testing

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Xue Jiang ◽  
Peter B. Lillehoj
Keyword(s):  
Interstitial Fluid ◽  
Point Of Care ◽  
Diagnostic Testing ◽  
Protein Detection ◽  
Lateral Flow ◽  
Lateral Flow Assay ◽  
Detection Sensitivity ◽  
Sample Collection ◽  
Protein Biomarkers ◽  
Skin Patch

Abstract Rapid diagnostic tests are one of the most commonly used tests to detect and screen for infectious diseases in the developing world. While these tests are simple, inexpensive, and readily available, they rely on finger-prick blood sampling, which requires trained medical personnel, poses risks of infection, and can complicate cooperation in young children, asymptomatic individuals, and communities with blood taboos. Here, we report a novel microneedle-based skin patch for the rapid detection of protein biomarkers in dermal interstitial fluid. Sample collection is facilitated by a hydrophilic hollow microneedle array that autonomously extracts and transports interstitial fluid to an antibody-based lateral flow test strip via surface tension for colorimetric antigen detection. We employ a simple gold enhancement treatment to enhance the detection sensitivity of this colloidal gold-based lateral flow assay and elucidate the underlying mechanism of this enhancement mechanism through experimental investigation. For proof-of-concept, this device was used to detect Plasmodium falciparum histidine-rich protein 2, a biomarker for malaria infection, which could be detected at concentrations as low as 8 ng/mL. Each test can be completed in <20 min and requires no equipment. To the best of our knowledge, this work is the first demonstration of a microneedle-based lateral flow assay for rapid protein detection in dermal interstitial fluid. In addition to its simplicity, minimally invasive nature, and low cost, this diagnostic device can be readily adapted to detect other protein biomarkers in interstitial fluid, making it a promising tool for point-of-care testing.

scholarly journals An Update on Advances in COVID-19 Laboratory Diagnosis and Testing Guidelines in India

2021 ◽  
Vol 9 ◽  
Author(s):  
K. S. Rajesh Kumar ◽  
Suhail Sayeed Mufti ◽  
Vinu Sarathy ◽  
Diganta Hazarika ◽  
Radheshyam Naik
Keyword(s):  
Large Scale ◽  
Vaccine Development ◽  
Point Of Care ◽  
Diagnostic Testing ◽  
Public Health Intervention ◽  
Laboratory Diagnosis ◽  
Accurate Diagnosis ◽  
Nucleic Acid Amplification ◽  
Rt Pcr ◽  
Outbreak Management

The declaration of COVID-19 as a global pandemic has warranted the urgent need for technologies and tools to be deployed for confirming diagnosis of suspected cases. Diagnostic testing for COVID-19 is critical for understanding epidemiology, contract-tracing, case management, and to repress the transmission of the SARS-CoV-2. Currently, the Nucleic Acid Amplification Test (NAAT)-based RT-PCR technique is a gold standard test used for routine diagnosis of COVID-19 infection. While there are many commercially available RT-PCR assay kits available in the market, selection of highly sensitive, specific, and validated assays is most crucial for the accurate diagnosis of COVID-19 infection. Laboratory diagnosis of SARS-CoV-2 is extremely important in the disease and outbreak management. Development of rapid point of care tests with better sensitivity and specificity is the critical need of the hour as this will help accurate diagnosis and aid in containing the spread of SARS-CoV-2 infection. Early detection of viral infection greatly enhances implementation of specific public health intervention, such as infection control, environmental decontamination, and the closure of specific high-risk zones. Large-scale sequencing of SARS-CoV-2 genome isolated from affected populations across the world needs to be carried to monitor mutations that might affect performance of molecular tests. Creation of genome repositories and open-source genetic databases for use by global researchers is clearly the way forward to manage COVID-19 outbreak and accelerate vaccine development. This review summarizes various molecular diagnostics methods, technical guidelines, and advanced testing strategies adopted in India for laboratory diagnosis of COVID-19.

scholarly journals LATE-PCR for LoC Molecular Diagnostics Devices and Its Application to the Sensitive Detection of SARS-CoV-2

2021 ◽  
Vol 6 (1) ◽  
pp. 43
Author(s):  
Dimitrios Karadimas ◽  
George Tsekenis
Keyword(s):  
Point Of Care ◽  
Low Cost ◽  
Diagnostic Testing ◽  
Heat Denaturation ◽  
Nasopharyngeal Swab ◽  
The Novel ◽  
Rt Pcr ◽  
Qualitative Detection ◽  
Novel Coronavirus ◽  
Real Patients

The emergence of the novel coronavirus, SARS-CoV-2, has highlighted the need for rapid, accurate, and point-of-care diagnostic testing. Lab-on-a-Chip (LoC) devices offer the possibility to run such tests at a low cost, while at the same time permitting the multiplexed detection of several viruses when coupled with microarray detection of the amplified products. Herein, we report the development of a protocol for the qualitative detection of SARS-CoV-2, through the design of appropriate primers that target the evolutionary conserved regions of the virus. The proposed protocol relies on an improved version of asymmetric RT-PCR, the linear-after-the-exponential (LATE)-PCR that uses primers that are deliberately designed for use at unequal concentrations. As a result, LATE-PCR exhibits similar efficiency to symmetric PCR, while promoting accumulation of single-stranded products that can subsequently hybridize to a single-strand DNA probe-spotted microarray. The performance of the developed LATE-PCR protocol was compared to that of symmetric RT-PCR, and validated with the use of artificial viral RNA and nasopharyngeal swab samples from real patients. Furthermore, and in order to illustrate its potential for integration into a biosensor platform, the amplicons were allowed to hybridize with probes that were covalently immobilized onto commercially available functionalized glass, without the need for heat denaturation.

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