Clinical Utility of a Highly Sensitive Lateral Flow Immunoassay as determined by Titer Analysis for the Detection of anti-SARS-CoV-2 Antibodies at the Point-of-Care

Coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), became a pandemic in early 2020. Lateral flow immunoassays for antibody testing have been viewed as a cheap and rapidly deployable method for determining previous infection with SARS-CoV-2; however, these assays have shown unacceptably low sensitivity. We report on nine lateral flow immunoassays currently available and compare their titer sensitivity in serum to a best-practice enzyme-linked immunosorbent assay (ELISA) and viral neutralization assay. For a small group of PCR-positive, we found two lateral flow immunoassay devices with titer sensitivity roughly equal to the ELISA; these devices were positive for all PCR-positive patients harboring SARS-CoV-2 neutralizing antibodies. One of these devices was deployed in Northern Italy to test its sensitivity and specificity in a real-world clinical setting. Using the device with fingerstick blood on a cohort of 27 hospitalized PCR-positive patients and seven hospitalized controls, ROC curve analysis gave AUC values of 0.7646 for IgG. For comparison, this assay was also tested with saliva from the same patient population and showed reduced discrimination between cases and controls with AUC values of 0.6841 for IgG. Furthermore, during viral neutralization testing, one patient was discovered to harbor autoantibodies to ACE2, with implications for how immune responses are profiled. We show here through a proof-of-concept study that these lateral flow devices can be as analytically sensitive as ELISAs and adopted into hospital protocols; however, additional improvements to these devices remain necessary before their clinical deployment.

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Comparative Analysis of the Euroimmun CXCL13 Enzyme-Linked Immunosorbent Assay and the ReaScan Lateral Flow Immunoassay for Diagnosis of Lyme Neuroborreliosis

Journal of Clinical Microbiology ◽

10.1128/jcm.00207-20 ◽

2020 ◽

Vol 58 (9) ◽

Author(s):

Katharina Ziegler ◽

Anca Rath ◽

Christoph Schoerner ◽

Renate Meyer ◽

Thomas Bertsch ◽

...

Keyword(s):

Immunosorbent Assay ◽

Roc Curve ◽

Point Of Care ◽

Lateral Flow ◽

Lyme Neuroborreliosis ◽

Diagnostic Tools ◽

Lateral Flow Immunoassay ◽

Enzyme Linked Immunosorbent Assay ◽

European Federation ◽

Point Of Care Test

ABSTRACT Diagnosis of Lyme neuroborreliosis (LNB) is challenging, as long as Borrelia-specific intrathecal antibodies are not yet detectable. The chemokine CXCL13 is elevated in the cerebrospinal fluid (CSF) of LNB patients. Here, we compared the performances of the Euroimmun CXCL13 enzyme-linked immunosorbent assay (CXCL13 ELISA) and the ReaScan CXCL13 lateral flow immunoassay (CXCL13 LFA), a rapid point-of-care test, to support the diagnosis of LNB. In a dual-center case-control study, CSF samples from 90 patients (34 with definite LNB, 10 with possible LNB, and 46 with other central nervous system [CNS] diseases [non-LNB group]) were analyzed with the CXCL13 ELISA and the CXCL13 LFA. Classification of patients followed the European Federation of Neurological Societies (EFNS) guidelines on LNB. The CXCL13 ELISA detected elevated CXCL13 levels in all patients with definite LNB (median, 1,409 pg/ml) compared to the non-LNB controls (median, 20.7 pg/ml; P < 0.0001), with a sensitivity of 100% and a specificity of 84.8% (cutoff value, 78.6 pg/ml; area under the receiver operating characteristic [ROC] curve, 0.93). Similarly, the CXCL13 LFA yielded elevated CXCL13 levels in 31 patients with definite LNB (median arbitrary value, 223.5) compared to the non-LNB control patients (median arbitrary value, 0; P < 0.0001) and had a sensitivity and specificity of 91.2% and 93.5%, respectively (cutoff arbitrary value, 22.5; area under the ROC curve, 0.94). The correlation between the CXCL13 levels obtained by ELISA and LFA was strong (Spearman correlation coefficient r = 0.89; P < 0.0001). The CXCL13 ELISA and the CXCL13 LFA are comparable diagnostic tools for the detection of CXCL13 in the CSF of patients with definite LNB. The advantage of the CXCL13 LFA is the shorter time to result.

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Acceptability, usability and performance of lateral flow immunoassay tests for SARS-CoV-2 antibodies: REACT-2 study of self-testing in non-healthcare key workers

Open Forum Infectious Diseases ◽

10.1093/ofid/ofab496 ◽

2021 ◽

Author(s):

Bethan Davies ◽

Marzieh Araghi ◽

Maya Moshe ◽

He Gao ◽

Kimberly Bennet ◽

...

Keyword(s):

Point Of Care ◽

Venous Blood ◽

Fire Service ◽

Lateral Flow ◽

Lateral Flow Immunoassay ◽

Antibody Testing ◽

Prevalence Studies ◽

Similar Performance ◽

Self Test ◽

The Uk

Abstract Background Seroprevalence studies are essential to understand the epidemiology of SARS-CoV-2. Various technologies, including laboratory assays and point-of-care self-tests, are available for antibody testing. The interpretation of seroprevalence studies requires comparative data on the performance of antibody tests. Methods In June 2020, current and former members of the UK Police forces and Fire service performed a self-test lateral flow immunoassay (LFIA), had a nurse-performed LFIA and provided a venous blood sample for ELISA . We present the prevalence of antibodies to SARS-CoV-2; the acceptability and usability of self-test LFIAs; and determine the sensitivity and specificity of LFIAs compared to laboratory ELISA. Results In this cohort of 5189 current and former members of the Police service and 263 members of the Fire service, 7.4% (396/5,348; 95% CI, 6.7-8.1) were antibody positive. Seroprevalence was 8.9% (6.9-11.4) in those under 40 years, 11.5% (8.8-15.0) in those of non-white ethnicity and 7.8% (7.1-8.7) in those currently working. Self-test LFIA had an acceptability of 97.7% and a usability of 90.0%. There was substantial agreement between within-participant LFIA results (kappa 0.80; 0.77-0.83). The LFIAs had a similar performance: compared to ELISA, sensitivity was 82.1% (77.7-86.0) self-test and 76.4% (71.9-80.5) nurse-performed with specificity of 97.8% (97.3-98.2) and 98.5% (98.1-98.8) respectively. Conclusion A greater proportion of this non-healthcare key worker cohort showed evidence of previous infection with SARS-CoV-2 than the general population at 6.0% (5.8-6.1) following the first wave in England. The high acceptability and usability reported by participants and similar performance of self-test and nurse-performed LFIAs indicate that the self-test LFIA is fit for purpose for home-testing in occupational and community prevalence studies.

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Diagnostic Performance of Assays for the Detection of Anti-Porcine Reproductive and Respiratory Syndrome Virus Antibodies in Serum and Muscle Transudate (“Meat Juice”) Based on Samples Collected under Experimental Conditions

Journal of Veterinary Diagnostic Investigation ◽

10.1177/104063870802000604 ◽

2008 ◽

Vol 20 (6) ◽

pp. 735-743 ◽

Cited By ~ 8

Author(s):

Ramon M. Molina ◽

Wayne Chittick ◽

Eric A. Nelson ◽

Jane Christopher-Hennings ◽

Raymond R. R. Rowland ◽

...

Keyword(s):

Neutralizing Antibodies ◽

Fluorescent Antibody ◽

Antibody Test ◽

Neutralization Assay ◽

Respiratory Syndrome Virus ◽

Enzyme Linked Immunosorbent Assay ◽

Antibody Testing ◽

Serum Samples ◽

Experimental Conditions ◽

Meat Juice

Three assays were evaluated for their ability to detect antibodies against Porcine reproductive and respiratory syndrome virus (PRRSV) in porcine muscle transudate (“meat juice”) samples. Samples were derived from 91 pigs inoculated with PRRSV isolate VR-2332 and 46 age-matched controls. Serum and muscle ( Musculus longissimus dorsi) samples were collected from randomly selected animals euthanized at ∼14-day intervals from 28 to 202 days postinoculation. Serum samples were assayed at a dilution of 1:40, and muscle transudate samples were assayed at 5 dilutions (1:2, 1:5, 1:10, 1:20, 1:40) using a commercial PRRSV antibody enzyme-linked immunosorbent assay (ELISA). In addition, muscle transudate samples were tested using an indirect fluorescent antibody test (IFAT) at 5 dilutions (1:2, 1:5, 1:10, 1:20, 1:40). Attempts to assay muscle transudate samples for neutralizing antibodies using a modified fluorescent focus neutralization assay were unsuccessful. Receiver operator characteristic (ROC) curve analyses were used to estimate cutoff thresholds and the associated diagnostic sensitivities and specificities for ELISA and IFAT at each dilution. For ELISA, muscle transudate samples at the ROC-optimized cutoffs were >95% sensitive and 100% specific at each dilution. At a cutoff dilution of ≥1:5, the IFAT diagnostic sensitivity and specificity of muscle transudate was estimated at 63.3% and 100%, respectively. These findings validated the use of muscle transudate samples in PRRSV surveillance programs based on ELISA antibody testing.

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SARS-CoV-2 Seroprevalence in Healthcare Workers of Kaunas Hospitals during the First Wave of the COVID-19 Pandemic

Medicina ◽

10.3390/medicina57020148 ◽

2021 ◽

Vol 57 (2) ◽

pp. 148 ◽

Cited By ~ 1

Author(s):

Laura Pereckaitė ◽

Asta Dambrauskienė ◽

Daiva Urbonienė ◽

Saulius Sadauskas ◽

Kęstutis Petrikonis ◽

...

Keyword(s):

Healthcare Workers ◽

Lateral Flow ◽

Immunoglobulin M ◽

Lateral Flow Immunoassay ◽

Enzyme Linked Immunosorbent Assay ◽

Antibody Testing ◽

Serum Samples ◽

Positive Group ◽

Percent Agreement ◽

Specific Igg

Background and objective: Serologic testing is a useful additional method for the diagnosis of COVID-19. It is also used for population-based seroepidemiological studies. The objective of the study was to determine SARS-CoV-2 seroprevalence in healthcare workers of Kaunas hospitals and to compare two methods for specific SARS-CoV-2 antibody testing. Materials and Methods: A total of 432 healthcare workers in Kaunas hospitals were enrolled in this study. Each participant filled a questionnaire including questions about their demographics, contact with suspected or confirmed COVID-19, acute respiratory symptoms, and whether they contacted their general practitioner, could not come to work, or had to be hospitalized. Capillary blood was used to test for SARS-CoV-2 specific immunoglobulin G (IgG) and immunoglobulin M (IgM) a lateral flow immunoassay. Serum samples were used to test for specific IgG and IgA class immunoglobulins using semiquantitative enzyme-linked immunosorbent assay (ELISA) method. Results: 24.77% of study participants had direct contact with a suspected or confirmed case of COVID-19. A total of 64.81% of studied individuals had at least one symptom representing acute respiratory infection, compatible with COVID-19. Lateral flow immunoassay detected SARS-CoV-2 specific IgG class immunoglobulins in 1.16% of the tested group. Fever, cough, dyspnea, nausea, diarrhea, headache, conjunctivitis, muscle pain, and loss of smell and taste predominated in the anti-SARS-CoV-2 IgG-positive group. Using ELISA, specific IgG were detected in 1.32% of the tested samples. Diarrhea, loss of appetite, and loss of smell and taste sensations were the most predominant symptoms in anti-SARS-CoV-2 IgG-positive group. The positive percent agreement of the two testing methods was 50%, and negative percent agreement was 99.66%. Conclusions: 1.16% of tested healthcare workers of Kaunas hospitals were anti-SARS-CoV-2 IgG-positive. The negative percent agreement of the lateral flow immunoassay and ELISA exceeded 99%.

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Quantitative assessment of AD markers using naked eyes: point-of-care testing with paper-based lateral flow immunoassay

Journal of Nanobiotechnology ◽

10.1186/s12951-021-01111-z ◽

2021 ◽

Vol 19 (1) ◽

Author(s):

Liding Zhang ◽

Xuewei Du ◽

Ying Su ◽

Shiqi Niu ◽

Yanqing Li ◽

...

Keyword(s):

Point Of Care ◽

Elisa Test ◽

Lateral Flow ◽

Lateral Flow Immunoassay ◽

Enzyme Linked Immunosorbent Assay ◽

Csf Biomarkers ◽

Transient Nature ◽

Prodromal Alzheimer’S Disease ◽

Csf Levels ◽

Point Of Care Detection

AbstractAβ42 is one of the most extensively studied blood and Cerebrospinal fluid (CSF) biomarkers for the diagnosis of symptomatic and prodromal Alzheimer’s disease (AD). Because of the heterogeneity and transient nature of Aβ42 oligomers (Aβ42Os), the development of technologies for dynamically detecting changes in the blood or CSF levels of Aβ42 monomers (Aβ42Ms) and Aβ42Os is essential for the accurate diagnosis of AD. The currently commonly used Aβ42 ELISA test kits usually mis-detected the elevated Aβ42Os, leading to incomplete analysis and underestimation of soluble Aβ42, resulting in a comprised performance in AD diagnosis. Herein, we developed a dual-target lateral flow immunoassay (dLFI) using anti-Aβ42 monoclonal antibodies 1F12 and 2C6 for the rapid and point-of-care detection of Aβ42Ms and Aβ42Os in blood samples within 30 min for AD diagnosis. By naked eye observation, the visual detection limit of Aβ42Ms or/and Aβ42Os in dLFI was 154 pg/mL. The test results for dLFI were similar to those observed in the enzyme-linked immunosorbent assay (ELISA). Therefore, this paper-based dLFI provides a practical and rapid method for the on-site detection of two biomarkers in blood or CSF samples without the need for additional expertise or equipment. Graphical Abstract

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