scholarly journals Assessing Immunity by Quantitative Measurement of SARS-CoV-2 IgG Antibodies in Fingerstick Samples

2021 ◽  
Author(s):  
Javier T. Garza ◽  
Jacob Quick ◽  
Dev Chatterjee ◽  
Robert Patrick Garr ◽  
Atul Varadhachary ◽  
...  
Keyword(s):  
Clinical Performance ◽  
Point Of Care ◽  
Treatment Options ◽  
Antibody Test ◽  
Cross Reactivity ◽  
International Standards ◽  
Antibody Concentration ◽  
Immune Protection ◽  
Igg Antibodies ◽  
Individual Level

COVID-19 has affected billions of people around the world directly or indirectly. The response to the pandemic has focused on preventing the spread of the disease and improving treatment options. Diagnostic technologies have played a key role in this response since the beginning of the pandemic. As vaccines and other treatments have been developed and deployed, interest in understanding and measuring the individual level of immune protection has increased. Historically, use of antibody titers to measure systemic immunity has been constrained by an incomplete understanding of the relationship between antibodies and immunity, the lack of international standards for antibody concentration to enable cross-study comparisons, and insufficient clinical data to allow for the development of robust antibody-immunity models. However, these constraints have recently shifted. With a deeper understanding of antibodies, the promulgation of WHO antibody standards, and the development of immunity models using datasets from multiple COVID-19 vaccine trials, certain types of quantitative antibody tests may now provide a way to monitor individual or community immunity against COVID-19. Specifically, tests that quantitate the concentration of anti-RBD IgG -antibodies that target the receptor binding domain of the S1 spike protein component of the SARS-CoV-2 virus- show promise as a useful and scalable measure of the COVID-19 immunity of both individuals and communities. However, to fulfill this promise, a rapid and easy-to-administer test is needed. To address this important clinical need, Brevitest deployed its point-of-care-capable technology platform that can run a rapid (<15 minute), quantitative antibody test with a sample of 10 µl of whole blood from a fingerstick. The test we validated on this platform measures the concentration of anti-RBD IgG in Binding Antibody Units per milliliter (BAU/mL) per WHO Reference Standard NIBSC 20/136. In this paper, we present studies used to characterize the Brevitest anti-RBD IgG assay and evaluate its clinical performance, lower limits of measurement, precision, linearity, interference, and cross-reactivity. The results demonstrate the ability of this assay to measure a patient's anti-RBD IgG concentration. This information, together with models developed from recent COVID-19 vaccine clinical trials, can provide a means of assessing the current level of immune protection of an individual or community against COVID-19 infection.

scholarly journals Improving access to new diagnostics through harmonised regulation: priorities for action

2014 ◽  
Vol 3 (1) ◽  
Author(s):  
Ruth McNerney ◽  
Kimberly Sollis ◽  
Rosanna W. Peeling
Keyword(s):  
Developing Countries ◽  
Diagnostic Tests ◽  
Clinical Performance ◽  
Point Of Care ◽  
Poor Quality ◽  
International Standards ◽  
Regulatory Oversight ◽  
Adoption And Implementation ◽  
Post Market ◽  
Timely Access

A new generation of diagnostic tests is being developed for use at the point of care that could save lives and reduce the spread of infectious diseases through early detection and treatment. It is important that patients in developing countries have access to these products at affordable prices and without delay. Regulation of medical products is intended to ensure safety and quality whilst balancing the need for timely access to beneficial new products. Current regulatory oversight of diagnostic tests in developing countries is highly variable and weak regulation allows poor-quality tests to enter the market. However, inefficient orover zealous regulation results in unnecessary delays, increases costs and acts as a barrier to innovation and market entry. Setting international standards and streamlining the regulatory process could reduce these barriers. Four priority activities have been identified where convergence of standards and protocols or joint review of data would be advantageous: (1) adoption of a common registration file for pre-market approval; (2) convergence of quality standards for manufacturing site inspections; (3) use of common evaluation protocols, aswell as joint review of data, to reduce unnecessary duplication of lengthy and costly clinical performance studies; and (4) use of networks of laboratories for post-market surveillance in order to monitor ongoing quality of diagnostic devices. The adoption and implementation of such measures in developing countries could accelerate access to new diagnostic tests that are safe and affordable.

scholarly journals Seroprevalence study of SARS-CoV-2 infection in General Practice in Ireland

BJGP Open ◽  
2021 ◽  
pp. BJGPO.2021.0038
Author(s):  
Michael Edmund O'Callaghan ◽  
Elizabeth Ryan ◽  
Cathal Walsh ◽  
Peter Hayes ◽  
Monica Casey ◽  
...  
Keyword(s):  
General Practice ◽  
Average Length ◽  
Point Of Care ◽  
Antibody Test ◽  
Igg Antibodies ◽  
Antibody Testing ◽  
Igg Antibody ◽  
Seroprevalence Study ◽  
History Of ◽  
Pcr Test

Background: SARS-CoV-2 antibody testing in community settings may help us better understand the immune response to this virus and therefore help guide public health efforts. Aim: Conduct a seroprevalence study of IgG antibodies in Irish GP clinics. Design and Setting: Participants were 172 staff and 799 patients of 15 general practices in the Midwest region of Ireland. Methods: This seroprevalence study utilised 2 manufacturers’ point-of-care (POC) SARS-CoV-2 IgM-IgG combined antibody tests, offered to patients and staff in general practice from mid-June to mid-July 2020. Results: Immunoglobulin G (IgG) seroprevalence was 12.6% in patients attending general practice and 11.1% in staff working in general practice, with administrative staff having the lowest seroprevalence at 2.5% and nursing staff having the highest at 17.6%. Previous symptoms suggestive of SARS-CoV-2 and history of a polymerase chain reaction (PCR) test were associated with higher seroprevalence. IgG antibodies were detected in approximately 80% of participants who had a previous PCR-confirmed infection. Average length of time between participants’ positive PCR test and positive IgG antibody test was 83 days. Conclusion: Patients and healthcare staff in general practice in Ireland had relatively high rates of IgG to SARS-CoV-2 compared to the national average at the time (1.7%). Four-fifths of participants with a history of confirmed COVID-19 disease still had detectable antibodies an average of 12 weeks post-infection. While not proof of immunity, SARS-CoV-2 POC testing can be used to estimate IgG seroprevalence in general practice settings.

scholarly journals Evaluation of the Truvian Easy Check COVID-19 IgM/IgG Lateral Flow Device for Rapid Anti-SARS-CoV-2 Antibody Detection

2020 ◽  
Author(s):  
Clarence W Chan ◽  
Sajid Shahul ◽  
Cheyenne Coleman ◽  
Vera Tesic ◽  
Kyle Parker ◽  
...  
Keyword(s):  
Clinical Performance ◽  
Reference Sample ◽  
Rapid Test ◽  
Antibody Test ◽  
Cross Reactivity ◽  
Antibody Detection ◽  
Antibody Assay ◽  
Widespread Application ◽  
Global Pandemic ◽  
Polymerase Chain

Abstract Objectives To evaluate the analytical and clinical performance of the Truvian Easy Check coronavirus disease 2019 (COVID-19) IgM/IgG anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody test. Serologic assays have become increasingly available for surveillance through the Food and Drug Administration emergency use authorization in the ongoing COVID-19 global pandemic. However, widespread application of serologic assays has been curbed by reports of faulty or inaccurate tests. Therefore, rapid COVID-19 antibody tests need to be thoroughly validated prior to their implementation. Methods The Easy Check device was analytically evaluated and its performance was compared with the Roche Elecsys anti-SARS-CoV-2 antibody assay. The test was further characterized for cross-reactivity using sera obtained from patients infected by other viruses. Clinical performance was analyzed with polymerase chain reaction-confirmed samples and a 2015 prepandemic reference sample set. Results The Easy Check device showed excellent analytical performance and compares well with the Roche Elecsys antibody assay, with an overall concordance of 98.6%. Clinical performance showed a sensitivity of 96.6%, a specificity of 98.2%, and an overall accuracy of 98.1%. Conclusions The Easy Check device is a simple, reliable, and rapid test for detection of SARS-CoV-2 seropositivity, and its performance compares favorably against the automated Roche Elecsys antibody assay.

scholarly journals Clinical performance of a point‐of‐care Coccidioides antibody test in dogs

2021 ◽  
Author(s):  
Krystle L. Reagan ◽  
Ian McHardy ◽  
George R. Thompson ◽  
Jane E. Sykes
Keyword(s):  
Clinical Performance ◽  
Point Of Care ◽  
Antibody Test

scholarly journals Clinical evaluation of the Abbott Alinity SARS-CoV-2 spike-specific quantitative IgG and IgM assays among infected, recovered, and vaccinated groups

2021 ◽  
Author(s):  
Madhusudhanan Narasimhan ◽  
Lenin Mahimainathan ◽  
Ellen Araj ◽  
Andrew E. Clark ◽  
John Markantonis ◽  
...  
Keyword(s):  
Immune Responses ◽  
Clinical Performance ◽  
Antibody Test ◽  
Cross Reactivity ◽  
Antibody Responses ◽  
Spike Protein ◽  
Clinical Sensitivity ◽  
Health Infrastructure ◽  
Archived Samples ◽  
Significant Burden

The COVID-19 pandemic continues to impose a significant burden on global health infrastructure. While identification and containment of new cases remains important, laboratories must now pivot and consider an assessment of SARS-CoV-2 immunity in the setting of the recent availability of multiple COVID-19 vaccines. Here we have utilized the latest Abbott Alinity semi-quantitative IgM and quantitative IgG spike protein (SP) serology assays (IgMSP and IgGSP) in combination with Abbott Alinity IgG nucleocapsid (NC) antibody test (IgGNC) to assess antibody responses in a cohort of 1236 unique participants comprised of naïve, SARS-CoV-2 infected, and vaccinated (including both naïve and recovered) individuals. The IgMSP and IgGSP assays were highly specific (100%) with no cross-reactivity to archived samples collected prior to the emergence of SARS-CoV-2, including those from individuals with seasonal coronavirus infections. Clinical sensitivity was 96% after 15 days for both IgMSP and IgGSP assays individually. When considered together, the sensitivity was 100%. A combination of NC- and SP-specific serologic assays clearly differentiated naïve, SARS-CoV-2-infected, and vaccine-related immune responses. Vaccination resulted in a significant increase in IgGSP and IgMSP values, with a major rise in IgGSP following the booster (second) dose in the naïve group. In contrast, SARS-CoV-2 recovered individuals had several fold higher IgGSP responses than naïve following the primary dose, with a comparatively dampened response following the booster. This work illustrates the strong clinical performance of these new serological assays and their utility in evaluating and distinguishing serological responses to infection and vaccination.

scholarly journals Post-Study Point-of-Care Oral Fluid Testing in HIV-1 Vaccinees

2020 ◽  
Author(s):  
Karina Oganezova ◽  
Elvin J Fontana-Martinez ◽  
Jon A Gothing ◽  
Alisha Pandit ◽  
Esther Kwara ◽  
...  
Keyword(s):  
Diagnostic Tests ◽  
Oral Fluid ◽  
Point Of Care ◽  
Antibody Test ◽  
Cross Reactivity ◽  
Fourth Generation ◽  
Hiv Screening ◽  
Hiv Test ◽  
Hiv 1

Abstract Background Experimental HIV-1 vaccines frequently elicit antibodies against HIV-1 which may react with commonly used HIV diagnostic tests, a phenomenon known as vaccine-induced seropositivity/seroreactivity (VISP/VISR). We sought to determine under clinic conditions if a patient-controlled HIV test, OraQuick ADVANCE Rapid HIV-1/2 Antibody Test, detected HIV-1 vaccine-induced antibodies. Methods Plasma assessment of HIV-1 cross-reactivity was examined in end-of-study samples from 57 healthy, HIV-uninfected participants who received a candidate vaccine which has entered Phase 2B and 3 testing. We also screened 120 healthy, HIV-uninfected, unblinded HIV-1 vaccine participants with VISP/VISR for an assessment using saliva. These participants came from 21 different parent vaccine protocols representing 17 different vaccine regimens, all of which contained an HIV-1 envelope immunogen. OraQuick ADVANCE was compared to results from concurrent blood samples using a series of commercial HIV screening immunoassays. Results Fifty-seven unique participant plasma samples were assayed in vitro and only one (1.8%) was reactive by OraQuick ADVANCE. None of the 120 clinic participants (0%, [95% CI 0% to 3.7%]) tested positive by OraQuick ADVANCE and all were confirmed to be uninfected by HIV-1 viral RNA testing. 118 of the 120 (98.3%) participants had a reactive HIV test for VISP/VISR: 77 (64%) had at least one reactive fourth-generation HIV-1 diagnostic test (p&lt;0.0001 vs no reactive OraQuick ADVANCE results) and 41 (34%) only had a reactive test by the less specific third-generation Abbott Prism assay. Conclusion These data suggest that this widely available patient-controlled test has limited reactivity to HIV-1 antibodies elicited by these candidate HIV-1 vaccines.

scholarly journals Upconverting phosphor technology-based lateral flow assay for the rapid and sensitive detection of anti-Trichinella spiralis IgG antibodies in pig serum

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Jian Li ◽  
Jing Ding ◽  
Xiao-Lei Liu ◽  
Bin Tang ◽  
Xue Bai ◽  
...  
Keyword(s):  
Trichinella Spiralis ◽  
Point Of Care ◽  
Cross Reactivity ◽  
Lateral Flow ◽  
Sensitive Detection ◽  
Parasitic Infections ◽  
Igg Antibodies ◽  
Point Of Care Test ◽  
Rabbit Igg ◽  
Pig Serum

Abstract Background Trichinella spiralis is a zoonotic food-borne parasite. A disease caused by infection with T. spiralis is called trichinellosis in humans. It is important to investigate the epidemic situation and the surveillance of herds and then prevent infection in humans. Therefore, this study is to develop a rapid and sensitive diagnostic method for on-site test in domestic and wild animals. Methods Upconverting phosphor nanoparticles (UCNPs), an excellent optical label, were conjugated with the excretory-secretory (ES) antigens from T. spiralis muscle larvae (ML) or goat anti-rabbit IgG, and a lateral flow (LF) assay based on these probes (UCNPs-ES/goat anti-rabbit IgG) was developed for the rapid and sensitive detection of anti-T. spiralis IgG antibodies in pig serum. The assay is named the UPT-LF-ES assay. In addition, the probes were characterized, and the assay was optimized. A cut-off threshold of the assay was also identified by using 169 known negative pig samples. Performance of the assay to T. spiralis with different infective numbers, cross-reactivity with other parasitic infections, the single-blinded experiment, and coincidence were evaluated with the assay. Results The UPT-LF-ES assay was successfully constructed and optimized based on the probes of UCNPs-ES/goat anti-rabbit IgG. In the pigs infected with 100, 1000, and 10,000 ML, positive results were first presented at 35 days post-infection (dpi), 30 dpi, and 25 dpi, respectively. The assay had no cross-reaction with other parasitic infections. A single-blinded experiment indicated that the sensitivity and specificity of the UPT-LF-ES assay were 100% and 100%, respectively, the area under the receiver operating characteristic (ROC) curve was 1.000. In addition, the value detected by the UPT-LF-ES assay was significantly different between positive and negative samples. Moreover, compared with the “gold standard” magnetic stirrer method, the coincidence rate of the UPT-LF-ES assay was 87.27%, and the kappa (K) coefficient was 0.7454, showing a substantial agreement. Conclusions The UPT-LF-ES assay is a useful point-of-care test (POCT) with T. spiralis in the detection of pig, which contributes to preventing human trichinellosis. Graphical Abstract

scholarly journals Clinical Performance Evaluation of a SARS-CoV-2 Rapid Antibody Test for Determining Past Exposure to SARS-CoV-2

2020 ◽  
Author(s):  
Peter Findeisen ◽  
Hugo Stiegler ◽  
Eloisa Lopez-Calle ◽  
Tanja Schneider ◽  
Eva Urlaub ◽  
...  
Keyword(s):  
Common Cold ◽  
Whole Blood ◽  
High Performance ◽  
Clinical Performance ◽  
Method Comparison ◽  
Antibody Test ◽  
Cross Reactivity ◽  
Percent Agreement ◽  
Antibody Tests ◽  
Rapid Antibody

The true prevalence and population seropositivity of SARS-CoV-2 infection remains unknown, due to the number of asymptomatic infections and limited access to high-performance antibody tests. To control the COVID-19 pandemic it is crucial to understand the true seroprevalence, but not every region has access to extensive centralized PCR and serology testing. Currently available rapid antibody tests lack the accuracy needed for recommendation by health authorities. To fill this gap, we analyzed and validated the clinical performance of a new point-of-care SARS-CoV-2 Rapid Antibody Assay, a chromatographic immunoassay for qualitative detection of IgM/IgG antibodies for use in near-patient settings. Analysis was performed using 42 Anti-SARS-Cov-2 positive (CoV+) and 92 Anti-SARS-Covid-2 negative (CoV-) leftover samples from before December 2019, using the Elecsys® Anti-SARS-CoV-2 as the reference assay. Analytical specificity was tested using leftover samples from individuals with symptoms of common cold collected before December 2019. The SARS-CoV-2 Rapid Antibody Test was 100.0% (95% CI 91.59-100.00) sensitive and 96.74% (95% CI 90.77-99.32) specific with an assay failure rate of 0.00%. No cross-reactivity was observed against the common cold panel. Method comparison was additionally conducted by two external laboratories, using 100 CoV+/275 CoV- samples, also comparing whole blood versus plasma matrix. The comparison demonstrated for plasma 96.00% positive/96.36% negative percent agreement with the Elecsys Anti-SARS-CoV-2 and overall 99.20% percent agreement between whole blood and EDTA plasma. The SARS-CoV-2 Rapid Antibody Test demonstrated similar clinical performance to the manufacturer's data and to a centralized automated immunoassay, with no cross-reactivity to common cold panels.

scholarly journals Rapid and sensitive point-of-care detection of Leptospira by RPA-CRISPR/Cas12a targeting lipL32

2022 ◽  
Vol 16 (1) ◽  
pp. e0010112
Author(s):  
Sirawit Jirawannaporn ◽  
Umaporn Limothai ◽  
Sasipha Tachaboon ◽  
Janejira Dinhuzen ◽  
Patcharakorn Kiatamornrak ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Clinical Performance ◽  
Point Of Care ◽  
Limited Resource ◽  
Cross Reactivity ◽  
Clinical Samples ◽  
Detection Assay ◽  
Short Palindromic Repeat ◽  
Flow Detection ◽  
Point Of Care Detection

Background One of the key barriers preventing rapid diagnosis of leptospirosis is the lack of available sensitive point-of-care testing. This study aimed to develop and validate a clustered regularly-interspaced short palindromic repeat (CRISPR)/CRISPR-associated protein 12a (CRISPR/Cas12a) platform combined with isothermal amplification to detect leptospires from extracted patient DNA samples. Methodology/Principal findings A Recombinase Polymerase Amplification (RPA)-CRISPR/Cas12a-fluorescence assay was designed to detect the lipL32 gene of pathogenic Leptospira spp. The assays demonstrated a limit of detection (LOD) of 100 cells/mL, with no cross-reactivity against several other acute febrile illnesses. The clinical performance of the assay was validated with DNA extracted from 110 clinical specimens and then compared to results from qPCR detection of Leptospira spp. The RPA-CRISPR/Cas12a assay showed 85.2% sensitivity, 100% specificity, and 92.7% accuracy. The sensitivity increased on days 4–6 after the fever onset and decreased after day 7. The specificity was consistent for several days after the onset of fever. The overall performance of the RPA-CRISPR/Cas12a platform was better than the commercial rapid diagnostic test (RDT). We also developed a lateral flow detection assay (LFDA) combined with RPA-CRISPR/Cas12a to make the test more accessible and easier to interpret. The combined LFDA showed a similar LOD of 100 cells/mL and could correctly distinguish between known positive and negative clinical samples in a pilot study. Conclusions/Significance The RPA-CRISPR/Cas12 targeting the lipL32 gene demonstrated acceptable sensitivity and excellent specificity for detection of leptospires. This assay might be an appropriate test for acute leptospirosis screening in limited-resource settings.

scholarly journals Updated Clinical Evaluation of the CLUNGENE® Rapid COVID-19 Antibody Test

Healthcare ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 1124
Author(s):  
Christopher C. Lamb ◽  
Fadi Haddad ◽  
Christopher Owens ◽  
Alfredo Lopez-Yunez ◽  
Marion Carroll ◽  
...  
Keyword(s):  
False Positive ◽  
Point Of Care ◽  
Rapid Test ◽  
Antibody Test ◽  
Cross Reactivity ◽  
Blood Collection ◽  
Rt Pcr ◽  
Antibody Testing ◽  
Reactivity Study ◽  
Positive Results

Background: COVID-19 antibody testing has been shown to be predictive of prior COVID-19 infection and an effective testing tool. The CLUNGENE® SARS-COV-2 VIRUS (COVID-19) IgG/IgM Rapid Test Cassette was evaluated for its utility to aide healthcare professionals. Method: Two studies were performed by using the CLUNGENE® Rapid Test. (1) An expanded Point-of-Care (POC) study at two clinical sites was conducted to evaluate 99 clinical subjects: 62 positive subjects and 37 negative subjects were compared to RT-PCR, PPA, and NPA (95% CI). Sensitivity was calculated from blood-collection time following symptom onset. (2) A cross-reactivity study was performed to determine the potential for false-positive results from other common infections. Results: The specificity of subjects with confirmed negative COVID-19 by RT-PCR was 100% (95% CI, 88.4–100.0%). The sensitivity of subjects with confirmed positive COVID-19 by RT-PCR was 96.77% (95% CI, 88.98–99.11%). In the cross-reactivity study, there were no false-positive results due to past infections or vaccinations unrelated to the SARS-CoV-2 virus. Conclusion: There is a need for a rapid, user-friendly, and inexpensive on-site monitoring system for diagnosis. The CLUNGENE® Rapid Test is a useful diagnostic test that provides results within 15 min, without high-complexity laboratory instrumentation.

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