scholarly journals A novel highly quantitative and reproducible assay for the detection of anti-SARS-CoV-2 IgG and IgM antibodies

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kenta Noda ◽  
Kouki Matsuda ◽  
Shigehiro Yagishita ◽  
Kenji Maeda ◽  
Yutaro Akiyama ◽  
...  
Keyword(s):  
Clinical Performance ◽  
High Sensitivity ◽  
Clinical Severity ◽  
Detection Accuracy ◽  
Serum Samples ◽  
Serological Tests ◽  
Nucleocapsid Proteins ◽  
Assay Performance ◽  
Quantification Accuracy ◽  
Antibody Levels

AbstractThe quantitative range and reproducibility of current serological tests for severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) are not optimized. Herein, we developed a diagnostic test that detects SARS-CoV-2 IgG and IgM with high quantitativeness and reproducibility and low interference. The system was based on the high-sensitivity chemiluminescence enzyme immunoassay (HISCL) platform and detects IgG and IgM specific to SARS-CoV-2 spike and nucleocapsid proteins. Quantification accuracy and reproducibility were evaluated using serially diluted samples from 60 SARS-CoV-2-infected patients. Assay performance was evaluated using serum samples from the SARS-CoV-2-infected patients and 500 SARS-CoV-2-negative serum samples collected before the emergence of SARS-CoV-2. The system showed high quantification accuracy (range, 102), high reproducibility (within 5%), and no cross-reaction between SARS1- and MERS-S proteins. Detection accuracy was 98.3% and 93.3% for IgG and IgM against spike proteins and 100% and 71.7% for IgG and IgM against nucleocapsid proteins, respectively. Mean antibody levels were > 10 times that in negative samples upon admission and > 100 times that at convalescent periods. Clinical severity upon admission was not correlated with IgG or IgM levels. This highly quantitative, reproducible assay system with high clinical performance may help analyze temporal serological/immunological profiles of SARS-CoV-2 infection and SARS-CoV-2 vaccine effectiveness.

scholarly journals Seroprevalence, waning, and correlates of anti-SARS-CoV-2 IgG antibodies in Tyrol, Austria: Large-scale study of 35,193 blood donors conducted between June 2020 and September 2021

2021 ◽  
Author(s):  
Anita Siller ◽  
Lisa Seekircher ◽  
Gregor A Wachter ◽  
Manfred Astl ◽  
Lena Tschiderer ◽  
...  
Keyword(s):  
Large Scale ◽  
Blood Donors ◽  
Participation Rate ◽  
Federal State ◽  
Igg Antibodies ◽  
Serum Samples ◽  
Serological Tests ◽  
Nucleocapsid Proteins ◽  
Antibody Levels ◽  
Prior Infection

Background: There is uncertainty about the seroprevalence of anti-SARS-CoV-2 antibodies in the general population of Austria, and about the extent to which antibodies elicited by vaccination or infection wane over time. Aim: To estimate seroprevalence, waning, and correlates of anti-SARS-CoV-2 IgG antibodies in the Federal State of Tyrol, Austria. Methods: We conducted a seroepidemiological study between June 2020 and September 2021, enrolling blood donors aged 18-70 years across Tyrol, Austria (participation rate 84.0%). We analysed serum samples for antibodies against spike or nucleocapsid proteins of SARS-CoV-2 with Abbott SARS-CoV-2 IgG assays. Results: We performed 47,363 serological tests among 35,193 individuals (median age 43.1 years [IQR: 29.3-53.7], 45.3% women, 10.0% with prior SARS-CoV-2 infection). Seroprevalence increased from 3.4% (95% CI: 2.8-4.2%) in June 2020 to 82.7% (95% CI: 81.4-83.8%) in September 2021, largely due to vaccination. Anti-spike IgG seroprevalence was 99.6% (99.4-99.7%) among fully vaccinated individuals, 90.4% (88.8-91.7%) among unvaccinated with prior infection, and 11.5% (10.8-12.3%) among unvaccinated without known prior infection. Anti-spike IgG levels were reduced by 44.0% (34.9-51.7%) at 5-6 months compared to 0-3 months after infection. In fully vaccinated individuals, they decreased by 31.7% (29.4-33.9%) per month. In multivariable adjusted analyses, both seropositivity among unvaccinated and antibody levels among fully vaccinated individuals were higher at young age (<25 years), higher with a known prior infection, and lower in current smokers. Conclusion: Seroprevalence in Tyrol increased to 82.7% in September 2021, with the bulk of seropositivity stemming from vaccination. Antibody levels substantially and gradually declined after vaccination or infection.

scholarly journals Long-Term Longitudinal Evaluation of Six Commercial Immunoassays for the Detection of IgM and IgG Antibodies against SARS CoV-2

Viruses ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1244
Author(s):  
Iulia Nedelcu ◽  
Raluca Jipa ◽  
Roxana Vasilescu ◽  
Cristian Băicuș ◽  
Costin-Ioan Popescu ◽  
...  
Keyword(s):  
Clinical Performance ◽  
Sample Selection ◽  
Early Time ◽  
Humoral Response ◽  
High Specificity ◽  
Data Interpretation ◽  
Serum Samples ◽  
Chemiluminescent Immunoassay ◽  
Chemiluminescent Microparticle Immunoassay ◽  
Antibody Levels

The number of serological assays for SARS-CoV-2 has skyrocketed in the past year. Concerns have been raised regarding their performance characteristics, depending on the disease severity and the time of the analysis post-symptom onset (PSO). Thus, independent validations using an unbiased sample selection are required for meaningful serology data interpretation. We aimed to assess the clinical performance of six commercially available assays, the seroconversion, and the dynamics of the humoral response to SARS-CoV-2 infection. The study included 528 serum samples from 156 patients with follow-up visits up to six months PSO and 161 serum samples from healthy people. The IgG/total antibodies positive percentage increased and remained above 95% after six months when chemiluminescent immunoassay (CLIA) IgG antiS1/S2 and electro-chemiluminescent assay (ECLIA) total antiNP were used. At early time points PSO, chemiluminescent microparticle immunoassay (CMIA) IgM antiS achieved the best sensitivity. IgM and IgG appear simultaneously in most circumstances, and when performed in parallel the sensitivity increases. The severe and the moderate clinical forms were significantly associated with higher seropositivity percentage and antibody levels. High specificity was found in all evaluated assays, but the sensitivity was variable depending on the time PSO, severity of disease, detection method and targeted antigen.

scholarly journals Serological Evaluation of Specific-Antibody Levels in Patients Treated for Chronic Chagas' Disease

2007 ◽  
Vol 15 (2) ◽  
pp. 297-302 ◽  
Author(s):  
Olga Sánchez Negrette ◽  
Fernando J. Sánchez Valdéz ◽  
Carlos D. Lacunza ◽  
María Fernanda García Bustos ◽  
María Celia Mora ◽  
...  
Keyword(s):  
Chagas Disease ◽  
Treatment Effectiveness ◽  
Enzyme Linked Immunosorbent Assay ◽  
Serum Samples ◽  
Serological Tests ◽  
Recombinant Antigens ◽  
Antibody Titers ◽  
Laboratory Procedures ◽  
The Individual ◽  
Antibody Levels

ABSTRACT Serological tests are the main laboratory procedures used for diagnosis during the indeterminate and chronic stages of Chagas' disease. A serological regression to negativity is the main criterion used to define parasitological cure in treated patients. The aim of this work was to monitor the individual specificities of antibody levels for 3 years posttreatment in 18 adult patients. Conventional serological techniques (hemagglutination assays and enzyme-linked immunosorbent assay [ELISA]) were modified by using recombinant antigens to detect early markers of treatment effectiveness. For this purpose, serum samples were taken before and during treatment and every 6 months after treatment for at least 3 years. When hemagglutination assays were used, a decrease in antibody levels was observed in only one patient. When ELISA with serum dilutions was used, antibody clearance became much more apparent: in 77.7% (14/18) of the patients, antibody titers became negative with time. This was observed at serum dilutions of 1/320 and occurred between the 6th and the 30th months posttreatment. The immune response and the interval for a serological regression to negativity were different for each patient. For some of the recombinant antigens, only 50% (9/18) of the patients reached the serological regression to negativity. Recombinant antigen 13 might be a good marker of treatment effectiveness, since 66.6% (six of nine) of the patients presented with an early regression to negativity for specific antibodies to this antigen (P = 0.002).

scholarly journals Comparison of Coombs Gel Test with ELISA and Standard Tube Agglutination Tests Used in Serological Diagnosis of Brucellosis

2020 ◽  
Vol 2 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Cigdem Akalan Kuyumcu ◽  
Serpil Erol ◽  
Rıza Adaleti ◽  
Seniha Senbayrak ◽  
Secil Deniz ◽  
...  
Keyword(s):  
Sensitivity And Specificity ◽  
Diagnostic Tests ◽  
Serological Test ◽  
High Sensitivity ◽  
Serological Diagnosis ◽  
Control Groups ◽  
Serum Samples ◽  
Serological Tests ◽  
Reliable Test ◽  
And Control

Objective: Serological tests are the most commonly used tests in the diagnosis of brucellosis; however, each serological test has some drawbacks. In this study, we aimed to determine the value of the Brucella Coombs gel test (BCGT) in the serological diagnosis of brucellosis in comparison with Standard tube agglutination (STA) and ELISA tests. Materials and Methods: The study included 42 patients who were considered to have brucellosis as a preliminary diagnosis. BCGT, Brucella-IgM/IgG ELISA, and STA tests were performed from serum samples of the patients. The correlation of the diagnostic tests was analyzed using Cohen’s Kappa Analysis.  Results: Twenty-seven (64.2%) of 42 patients were diagnosed with brucellosis according to their medical history and clinical and serological tests. The sensitivity and specificity of BCGT to diagnose brucellosis was 96.2%, and 100%, respectively. The sensitivity and specificity for the diagnosis of brucellosis 62.9% and 100% for STA, respectively; 33.3% and 66.6% for Brucella-IgM; and 66.6% and 100% for Brucella-IgG. BCGT was significantly correlated with STA (κ= 0.590) and Brucella-IgG (κ=0.539) Conclusion: BCGT can be utilized as a simple and reliable test in the diagnosis of brucellosis with high sensitivity and specificity. Nevertheless, the sensitivity and specificity of BCGT should be demonstrated by comprehensive studies, including culture-confirmed cases and control groups.

scholarly journals Tetanus Immunity among Women Aged 15 to 39 Years in Cambodia: a National Population-Based Serosurvey, 2012

2016 ◽  
Vol 23 (7) ◽  
pp. 546-554 ◽  
Author(s):  
Heather M. Scobie ◽  
Bunsoth Mao ◽  
Sokhal Buth ◽  
Kathleen A. Wannemuehler ◽  
Charlotte Sørensen ◽  
...  
Keyword(s):  
High Sensitivity ◽  
Population Based ◽  
Enzyme Linked Immunosorbent Assay ◽  
Cluster Sampling ◽  
Serum Samples ◽  
Nulliparous Women ◽  
Vaccination Campaigns ◽  
Antibody Levels ◽  
Multiple Pathogens ◽  
Tetanus Immunity

To monitor progress toward maternal and neonatal tetanus elimination (MNTE) in Cambodia, we conducted a nationwide serosurvey of tetanus immunity in 2012. Multistage cluster sampling was used to select 2,154 women aged 15 to 39 years. Tetanus toxoid antibodies in serum samples were measured by gold-standard double-antigen enzyme-linked immunosorbent assay (DAE) and a novel multiplex bead assay (MBA). Antibody concentrations of ≥0.01 IU/ml by DAE or the equivalent for MBA were considered seroprotective. Estimated tetanus seroprotection was 88% (95% confidence interval [CI], 86 to 89%); 64% (95% CI, 61 to 67%) of women had antibody levels of ≥1.0 IU/ml. Seroprotection was significantly lower (P< 0.001) among women aged 15 to 19 years (63%) and 20 to 24 years (87%) than among those aged ≥25 years (96%), among nulliparous women than among parous women (71 versus 97%), and among those living in the western region than among those living in other regions (82 versus 89%). The MBA showed high sensitivity (99% [95% CI, 98 to 99%]) and specificity (92% [95% CI, 88 to 95%]) compared with DAE. Findings were compatible with MNTE in Cambodia (≥80% protection). Tetanus immunity gaps should be addressed through strengthened routine immunization and targeted vaccination campaigns. Incorporating tetanus testing in national serosurveys using MBAs, which can measure immunity to multiple pathogens simultaneously, may be beneficial for monitoring MNTE.

scholarly journals Diagnostic-test evaluation of immunoassays for anti-Toxoplasma gondii IgG antibodies in a random sample of Mexican population

2014 ◽  
Vol 8 (05) ◽  
pp. 642-647 ◽  
Author(s):  
Heriberto Caballero-Ortega ◽  
Rocío Castillo-Cruz ◽  
Sandra Murieta ◽  
Luz Belinda Ortíz-Alegría ◽  
Esther Calderón-Segura ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
Western Blot ◽  
Latin American ◽  
High Sensitivity ◽  
Reference Standards ◽  
Igg Antibodies ◽  
Serum Samples ◽  
Serological Tests ◽  
Western Blots ◽  
Open Population

Introduction: There are few articles on evaluation of Toxoplasma gondii serological tests. Besides, commercially available tests are not always useful and are expensive for studies in open population. The aim of this study was to evaluate in-house ELISA and western blot for IgG antibodies in a representative sample of people living in Mexico. Methodology: Three hundred and five serum samples were randomly selected from two national seroepidemiological survey banks; they were taken from men and women of all ages and from all areas of the country. ELISA cut-off was established using the mean plus three standard deviations of negative samples. Western blots were analysed by two experienced technicians and positivity was established according to the presence of at least three diagnostic bands. A commercial ELISA kit was used as a third test. Two reference standards were built up: one using concordant results of two assays leaving the evaluated test out and the other in which the evaluated test was included (IN) with at least two concordant results to define diagnosis. Results: the lowest values of diagnostic parameters were obtained with the OUT reference standards: in-house ELISA had 96.9% sensitivity, 62.1% specificity, 49.6% PPV, 98.1% NPV and 71.8% accuracy, while western blot presented 81.8%, 89.7%, 84.0%, 88.2% and 86.6% values and the best kappa coefficient (0.72-0.82). Conclusions: The in-house ELISA is useful for screening people of Mexico, due to its high sensitivity, while western blot may be used to confirm diagnosis. These techniques might prove useful in other Latin American countries.

scholarly journals COMPARISON OF PERFORMANCE CHARACTERISTICS BETWEEN LATERAL FLOW, ELISAAND ELECTROCHEMILUMINESCENCE IMMUNOASSAYS FOR THE DETECTION OF SARS-COV-2 ANTIBODIES AMONG HEALTHCARE WORKERS

2021 ◽  
pp. 45-48
Author(s):  
Shincy M R ◽  
Vandana Govindan ◽  
Sudhakar H H ◽  
Padmapriya K ◽  
Venkatesha V T ◽  
...  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Healthcare Workers ◽  
Care Pathway ◽  
Point Of Care ◽  
High Sensitivity ◽  
Central Research ◽  
Serum Samples ◽  
Igg Antibody ◽  
Human Igg ◽  
Serological Tests

Background: The detection of SARS-CoV-2 IgG is important to determine the course of COVID-19. Medical professionals and researchers have been urging the need for wide and rapid testing of citizens in order to plan measures that can contain the spread of the virus. Antibody tests play an important role throughout the patient care pathway and are vital for the management and surveillance of the virus. Although RTPCR is considered to be the gold standard, serological tests based on antibodies could be very helpful for on-time detection. We performed one to one assessment of electrochemiluminescence immunoassay, enzyme immunoassay (EIAs), and point-of-care lateral ow assay (POCTs) to detect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) IgG antibody. Materials and Methods: 611 healthcare workers were recruited between November and December 2020 at Central Research Laboratory, KIMS. ® Collected serum samples were analysed using three commercially available assays: the Elecsys , Anti-SARS CoV-2 Human IgG ELISA, the Standard Q IgG/IgM combo assay following the manufacturer's protocol to measure the IgG titer of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Results:The kits displayed a sensitivity of 91.8%, 79.5% ,61.2% and a specicity of 80.2%, 64.1% ,61.7% in order. Conclusion: ® Our results indicate a high sensitivity and specicity for the Elecsys assay compared to Anti-SARS CoV-2 Human IgG ELISA, the Standard Q IgG/IgM combo assays.

scholarly journals Concordance of “rapid” serological tests and IgG and IgM chemiluminescence for SARS-COV-2

2020 ◽  
Author(s):  
K Sáenz-Flor ◽  
L y Sanatafé
Keyword(s):  
Clinical Performance ◽  
Disease Onset ◽  
Kappa Index ◽  
Serum Samples ◽  
Serological Tests ◽  
Demand And Supply ◽  
Diagnostic Test Evaluation ◽  
Negative Findings ◽  
Serological Studies ◽  
Rapid Tests

AbstarctBackgroundThe COVID-19 serological tests for IgG and IgM have been developed with several methodologies: Immunoenzymatic Assay (ELISA), Chemiluminescence, Electro Chemiluminescence, Fluorescent Lateral Flow Immunoassays and Immunochromatography. None of these tests should be used for the diagnosis or population screening of the disease, considering that the antibodies appear only on the 8th – 14th day of the disease onset. The present study evaluates a sample of immunofluorescent and immunochromatographic rapid tests to show their agreement in relation to Chemiluminescence.MethodsA diagnostic test evaluation assay was performed to establish the performance of five “rapid” tests (4 immunochromatographic and 1 immunofluorescent tests) for IgG and IgM serology for SARS-CoV-2 using a panel of 30 serum samples from patients received in the laboratory analysis routine. For the evaluation of clinical performance, the qualitative results of the “rapid” tests were compared against those obtained by chemiluminescence, dichotomized as positives (≥ 10 AU / mL) or negative (<10 UA / mL).FindingsThe best agreement is seen in the immunofluorescent assay, for the IgG contrast, with a particularly good kappa index (0.85), without positive disagreements and a negative disagreement of about 15%. In the immunochromatographic methods Kappa index was 0.61 at best, with disagreements in negative findings of ≈35% and in positive cases of up to ≈70%.The IgM concordance behavior, on the other hand, reflects a weak to moderate Kappa concordance value (Kappa 0.2 to 0.6), with negative disagreements reaching up to 55% and positives of up to 84%, without any evaluated test reaching Kappa performance equal to or greater than 0.8.InterpretationSerological studies should be used in the clinical and epidemiological context and of other diagnostic tests. Given the high demand and supply in the market of “rapid serological tests”, its evaluation against panels of serologically positive or negative samples established by Chemiluminescence or Electro chemiluminescence is essential to authorize its extensive use in populationsFundingNone

scholarly journals Test performance evaluation of SARS-CoV-2 serological assays

2020 ◽  
Author(s):  
Jeffrey D. Whitman ◽  
Joseph Hiatt ◽  
Cody T. Mowery ◽  
Brian R. Shy ◽  
Ruby Yu ◽  
...  
Keyword(s):  
Test Performance ◽  
Severe Disease ◽  
Cross Reactivity ◽  
Time Interval ◽  
Rt Pcr ◽  
Serum Samples ◽  
Serological Tests ◽  
Full Spectrum ◽  
Assay Performance ◽  
Lateral Flow Assays

ABSTRACTBackgroundSerological tests are crucial tools for assessments of SARS-CoV-2 exposure, infection and potential immunity. Their appropriate use and interpretation require accurate assay performance data.MethodWe conducted an evaluation of 10 lateral flow assays (LFAs) and two ELISAs to detect anti-SARS-CoV-2 antibodies. The specimen set comprised 130 plasma or serum samples from 80 symptomatic SARS-CoV-2 RT-PCR-positive individuals; 108 pre-COVID-19 negative controls; and 52 recent samples from individuals who underwent respiratory viral testing but were not diagnosed with Coronavirus Disease 2019 (COVID-19). Samples were blinded and LFA results were interpreted by two independent readers, using a standardized intensity scoring system.ResultsAmong specimens from SARS-CoV-2 RT-PCR-positive individuals, the percent seropositive increased with time interval, peaking at 81.8-100.0% in samples taken >20 days after symptom onset. Test specificity ranged from 84.3-100.0% in pre-COVID-19 specimens. Specificity was higher when weak LFA bands were considered negative, but this decreased sensitivity. IgM detection was more variable than IgG, and detection was highest when IgM and IgG results were combined. Agreement between ELISAs and LFAs ranged from 75.8-94.8%. No consistent cross-reactivity was observed.ConclusionOur evaluation showed heterogeneous assay performance. Reader training is key to reliable LFA performance, and can be tailored for survey goals. Informed use of serology will require evaluations covering the full spectrum of SARS-CoV-2 infections, from asymptomatic and mild infection to severe disease, and later convalescence. Well-designed studies to elucidate the mechanisms and serological correlates of protective immunity will be crucial to guide rational clinical and public health policies.

Use of serum biomarkers to differentiate benign breast lesions from invasive breast cancer in women with a BI-RADS 3 or 4.

2014 ◽  
Vol 32 (26_suppl) ◽  
pp. 20-20
Author(s):  
Meredith C. Henderson ◽  
Michael Silver ◽  
Susan Yeh ◽  
Christa Corn ◽  
Sherri Borman ◽  
...  
Keyword(s):  
Breast Imaging ◽  
Clinical Decision Making ◽  
Serum Proteins ◽  
Clinical Performance ◽  
Imaging Techniques ◽  
High Sensitivity ◽  
Serum Biomarkers ◽  
Serum Samples ◽  
Meso Scale Discovery ◽  
Multiple Imaging

20 Background: The Provista Biomarker Assay (PBA) combines multiple serum biomarkers, measured at high sensitivity, in order to determine the likelihood of an invasive breast tumor at the time of testing. PBA, when paired with traditional breast imaging technologies, provides a biochemical tool that can help guide additional imaging or biopsy decisions. As part of our ongoing efforts to characterize clinical performance, we conducted a proof-of-concept study wherein PBA assay performance was tested in prospectively enrolled BI-RADS 3 and 4 patients. Methods: To maximize performance and sensitivity, we utilized the Meso Scale Discovery ELISA-based system to analyze a randomized cohort of 350 prebiopsy serum samples from women under the age of 50. Enrollment in the trial required a BI-RADS 3 or 4 radiologic assessment utilizing multiple imaging modalities. Serum proteins and autoantibodies were measured for each patient and applied to a proprietary statistical algorithm. Results: We were able to obtain statistically significant differentiation using the Provista Biomarker Assay in women under age 50 who were characterized as BI-RADS 3 or 4. The majority of patients in the study were diagnosed with a benign breast lesion, consistent with prior studies. However, the data indicate that PBA, when used in combination with imaging techniques, more accurately informs clinical decision-making. Conclusions: The Provista Biomarker Assay provides a powerful tool for physicians to more accurately assess patients with a BI-RADS 3 or 4 classification. With more clinical evidence, the assay may translate into changes in clinical treatment decisions for women under the age of 50 with a BI-RADS 3 or 4 classification. Clinical trial information: NCT01839045.

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