Comparison of the SARS-CoV-2 spike protein ELISA and the Abbott Architect SARS-CoV-2 IgG nucleocapsid protein assays for detection of antibodies.
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ABSTRACT:
SUBMITTER: Wadhwa A
PROVIDER: S-EPMC8320896 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:IntroductionWe evaluated the Roche Elecsys Anti-SARS-CoV-2 and Snibe SARS-CoV-2 S-RBD IgG spike chemiluminescent immunoassays and compared them to existing Roche/Abbott nucleocapsid and Abbott IgM spike assays.MethodsWe enrolled 184 SARS-CoV-2 RT-PCR positive samples and 215 controls (172 pre-pandemic, and 43 cross-reactivity) to evaluate the Roche spike antibody (anti-SARS-CoV-2-S) assay. For the Snibe evaluation, we included 119 RT-PCR positive samples and 249 controls (200 pre-pandemice, 49 cross-reactivity). 98 cases had been tested on three spike assays (Roche total antibody, Snibe IgG and Abbott IgM).ResultsThe Roche anti-SARS-CoV-2-S assay had a CV of 0.5% (0.82U/mL) and 2.3% (8.72U/mL) and was linear from 1.16 to 240U/mL. The Snibe assay was linear from 6.43 to 77.7AU/mL, CV of 5.5% (0.43AU/mL) and 8.8% (0.18AU/mL). The Snibe spike assay was significantly more sensitive than the Abbott IgG assay at 0-6 days POS (35.2% vs 3.6%, mean difference 29.6%, 95% CI 17.5 to 41.8, p < 0.0001). Optimized LORs significantly improved the sensitivity of the Roche spike (48.1%-56.7%) and both nucleocapsid assays (Roche 43.3%-65.5%, Abbott 3.6%-18.5%) in early disease.ConclusionAlthough both spike assays showed higher sensitivity than their nucleocapsid counterparts, lower, optimized LORs provided the most significant improvements to sensitivity.
| S-EPMC8513513 | biostudies-literature
Project description:BackgroundClinical laboratory testing has been an essential part of COVID-19 management. Serology can provide valuable information regarding a patient's exposure to virus, and may have a larger role to play as vaccines becomes available. Limited data is available on the serological response in pediatric patients. Here we investigate the use of one manufacturer's commercial assays for detecting IgM and IgG in an exclusively pediatric population.MethodsAbbott SARS-CoV-2 IgM and IgG assays were performed on an Abbott ARCHITECT i1000. For specificity studies, we tested 78 patient specimens collected before the COVID-19 pandemic, and 66 specimens from patients who tested negative for SARS-CoV-2 nucleic acid amplification test (NAAT) during the COVID-19 pandemic. For sensitivity we tested 181 specimens from 41 patients with a positive NAAT result. Precision data was acquired for 20 days.ResultsFor IgM, the highest qualitative positive agreement with molecular results was observed to be 15-30 days after a positive NAAT result or after symptom onset. For IgG, the highest positive agreement was 31-60 days after a positive NAAT result or 61-90 days after the start of symptoms. IgM started to decline 30 days after NAAT results and faded by 90 days. IgG started to decrease 60 days after a positive NAAT result.ConclusionThe Abbott IgM and IgG assays have negative agreements of 98.7-100% relative to NAAT results. The IgM and IgG levels assayed by these methods start to decline months after positive molecular results and onset of symptoms in a pediatric population.
| S-EPMC7893289 | biostudies-literature
Project description:Critical evaluation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) serologic assays is needed to guide clinical decision-making and ensure that these assays provide optimal benefit to patients and the public. Here, three commercially available assays with widespread distribution capabilities are compared. A total of 667 specimens, 103 from patients with confirmed SARS-CoV-2 infections and 564 collected prior to the emergence of SARS-CoV-2, were analyzed in parallel using the Roche Elecsys SARS-CoV-2 total antibody and Abbott Alinity SARS-CoV-2 IgG assays; a subset of 55 samples from patients with confirmed SARS-CoV-2 infections was additionally evaluated using the Abbott Architect SARS-CoV-2 IgM assay. Qualitative agreement between the Abbott IgG and Roche total antibody assays was 98.7% (658/667), with Cohen's kappa value of 0.919 (95% confidence interval [CI], 0.867 to 0.972). Qualitative agreements with the Abbott IgM assay were 92.7% (51/55, Abbott IgG) and 85.5% (47/55, Roche total antibody). Diagnostic specificities determined using pre-COVID-19 samples for the Abbott IgG and Roche total antibody assays were 99.65% (95% CI, 98.72 to 99.90%) and 100.00% (95% CI, 99.32 to 100.00%), respectively, spanning claims made by each manufacturer. Diagnostic sensitivities increased for all three assays with increasing time since the onset of symptoms. Among 51 patients with confirmed SARS-CoV-2 infections, 23 (45.1%), 24 (47.1%), and 22 (43.1%) were reactive by the Abbott IgG, Roche total antibody, and Abbott IgM assays, respectively, with sampling times 0 to 56 days post-positive PCR (median/mean, 2/6.2 days). Combining IgG and IgM screening identified 4/55 additional samples with detectable antibodies that would not have been observed using the assays independently. Notably, one immunocompromised patient with confirmed SARS-CoV-2 infection showed no detectable antibodies using any of the three assays 43 days after onset of symptoms.
| S-EPMC7771433 | biostudies-literature
Project description:ObjectivesCoronavirus disease-19 (COVID-19) pandemic became the greatest public health challenge globally. Study of dynamicity and durability of naturally developed antibodies against SARS-CoV-2 are of great importance from an epidemiological viewpoint.MethodsIn this observational cohort study, we have followed up the 76 individuals who tested positive for SARS-CoV-2 infection by real-time reverse transcriptase-polymerase chain reaction (RT-qPCR) for 16 weeks (post-enrolment) to record the periodic changes in titre, concentration, clinical growth and persistence of naturally developed SARS-CoV-2 antibodies. We collected serum samples from these individuals for 16 weeks with a frequency of weekly and fortnightly during each follow-up and tested them in two CLIA-based platforms (Abbott Architect i1000SR and Roche Cobas e411) for testing SARS-CoV-2 antibodies both qualitatively and quantitatively.ResultsWe recorded the antibody magnitude of these individuals 10 times between September 2020 and February 2021. We found a waning of antibodies against nucleocapsid antigen protein but not a complete disappearance by the end of 16 weeks. Out of 76 cases, 30 cases (39.47%) became seronegative in qualitative assay, although all the sera samples (100%) remained positive when tested in quantitative assay.ConclusionThe lower persistence of anti-nucleocapsid SARS-CoV-2 antibody may not be the exact phenomenon as those cases were still seropositive against spike protein and help in neutralising the virus.
| S-EPMC8249824 | biostudies-literature
Project description:There is an urgent need for an accurate antibody test for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We have developed 3 ELISA methods, trimer spike IgA, trimer spike IgG, and nucleocapsid IgG, for detecting anti-SARS-CoV-2 antibodies. We evaluated their performance along with four commercial ELISAs, EDI™ Novel Coronavirus COVID-19 ELISA IgG and IgM, Euroimmun Anti-SARS-CoV-2 ELISA IgG and IgA, and one lateral flow assay, DPP® COVID-19 IgM/IgG System (Chembio). Both sensitivity and specificity were evaluated and the probable causes of false-positive reactions were determined. The assays were evaluated using 300 pre-epidemic samples and 100 PCR-confirmed COVID-19 samples. The sensitivities and specificities of the assays were as follows: 90%/100% (in-house trimer spike IgA), 90%/99.3% (in-house trimer spike IgG), 89%/98.3% (in-house nucleocapsid IgG), 73.7%/100% (EDI nucleocapsid IgM), 84.5%/95.1% (EDI nucleocapsid IgG), 95%/93.7% (Euroimmun S1 IgA), 82.8%/99.7% (Euroimmun S1 IgG), 82.0%/91.7% (Chembio nucleocapsid IgM), 92%/93.3% (Chembio nucleocapsid IgG). The presumed causes of false positive results from pre-epidemic samples in commercial and in-house assays were mixed. In some cases, assays lacked reproducibility. In other cases, reactivity was abrogated by competitive inhibition (spiking the sample with the same antigen that was used for coating ELISAs prior to performing the assay), suggesting positive reaction could be attributed to the presence of antibodies against these antigens. In other cases, reactivity was consistently detected but not abrogated by the spiking, suggesting positive reaction was not attributed to the presence of antibodies against these antigens. Overall, there was wide variability in assay performance using our samples, with in-house tests exhibiting the highest combined sensitivity and specificity. The causes of "false positivity" in pre-epidemic samples may be due to plasma antibodies apparently reacting with the corresponding antigen, or spurious reactivity may be directed against non-specific components in the assay system. Identification of these targets will be essential to improving assay performance.
| S-EPMC7605638 | biostudies-literature
Project description:BackgroundLaboratory-based methods for SARS-CoV-2 antibody detection vary widely in performance. However, there are limited prospectively-collected data on assay performance, and minimal clinical information to guide interpretation of discrepant results.MethodsOver a 2-week period, 1080 consecutive plasma samples submitted for clinical SARS-CoV-2 IgG testing were tested in parallel for anti-nucleocapsid IgG (anti-N, Abbott) and anti-spike IgG (anti-S1, EUROIMMUN). Chart review was conducted for samples testing positive or borderline on either assay, and for an age/sex-matched cohort of samples negative by both assays. CDC surveillance case definitions were used to determine clinical sensitivity/specificity and conduct receiver operating characteristics curve analysis.ResultsThere were 52 samples positive by both methods, 2 positive for anti-N only, 34 positive for anti-S1 only, and 27 borderline for anti-S1. Of the 34 individuals positive for anti-S1 alone, 8 (24%) had confirmed COVID-19. No anti-S1 borderline cases were positive for anti-N or had confirmed/probable COVID-19. The anti-N assay was less sensitive (84.2% [95% CI 72.1-92.5%] vs 94.7% [95% CI 85.4-98.9%]) but more specific (99.2% [95% CI 95.5-100%] vs 86.9% [95% CI 79.6-92.3%]) than anti-S1. Abbott anti-N sensitivity could be improved to 96.5% with minimal effect on specificity if the index threshold was lowered from 1.4 to 0.6.ConclusionReal-world concordance between different serologic assays may be lower than previously described in retrospective studies. These findings have implications for the interpretation of SARS-CoV-2 IgG results, especially with the advent of spike antigen-targeted vaccination, as a subset of patients with true infection are anti-N negative and anti-S1 positive.
| S-EPMC7989591 | biostudies-literature
Project description:Early detection and identification of SARS-CoV-infected patients and actions to prevent transmission are absolutely critical to prevent another SARS outbreak. Antibodies that specifically recognize the SARS-CoV spike and nucleocapsid proteins may provide a rapid screening method to allow accurate identification and isolation of patients with the virus early in their infection. For this reason, we raised peptide-induced polyclonal antibodies against SARS-CoV spike protein and polyclonal antibodies against SARS-CoV nucleocapsid protein using 6x His nucleocapsid recombinant protein. Western blot analysis and immunofluorescent staining showed that these antibodies specifically recognized SARS-CoV.
| S-EPMC7111193 | biostudies-literature
Project description:There is an urgent need for an accurate antibody test for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). In this paper, we have developed 3 ELISA methods, trimer spike IgA, trimer spike IgG, and nucleocapsid IgG, for detecting anti-SARS-CoV-2 antibodies. We evaluated their performance in comparison with four commercial ELISAs, EDI™ Novel Coronavirus COVID-19 ELISA IgG and IgM, Euroimmun Anti-SARS-CoV-2 ELISA IgG and IgA, and one lateral flow assay, DPP® COVID-19 IgM/IgG System (Chembio). Both sensitivity and specificity were evaluated and the causes of false-positive reactions were determined. The assays were compared using 300 pre-epidemic samples and 100 PCR-confirmed COVID-19 samples. The sensitivities and specificities of the assays were as follows: 90%/100% (in-house trimer spike IgA), 90%/99.3% (in-house trimer spike IgG), 89%/98.3% (in-house nucleocapsid IgG), 73.7%/100% (EDI nucleocapsid IgM), 84.5%/95.1% (EDI nucleocapsid IgG), 95%/93.7% (Euroimmun S1 IgA), 82.8%/99.7% (Euroimmun S1 IgG), 82.0%/91.7% (Chembio nucleocapsid IgM), 92%/93.3% (Chembio nucleocapsid IgG). The presumed causes of positive signals from pre-epidemic samples in commercial and in-house assays were mixed. In some cases, positivity varied with assay repetition. In other cases, reactivity was abrogated by competitive inhibition (spiking the sample with analyte prior to performing the assay). In other cases, reactivity was consistently detected but not abrogated by analyte spiking. Overall, there was wide variability in assay performance using our samples, with in-house tests exhibiting the highest combined sensitivity and specificity. The causes of "false positivity" in pre-epidemic samples may be due to plasma antibodies apparently reacting with the analyte, or spurious reactivity may be directed against non-specific components in the assay system. Identification of these targets will be essential to improving assay performance.
| S-EPMC7418763 | biostudies-literature
Project description:Coronavirus 2019 (COVID-19) is a global concern for public health. Thus, early and accurate diagnosis is a critical step in management of this infectious disease. Currently, RT-PCR is routine diagnosis test for COVID-19, but it has some limitations and false negative results. enzyme-linked immunosorbent assay (ELISA) against SARS-CoV-2 antigens seems to be an appropriate approach for serodiagnosis of COVID-19. In the current study, an ELISA system, using a recombinant nucleocapsid (N) protein, was developed for the detection of IgM and IgG antibodies to SARS-CoV-2. The related protein was expressed, purified, and used in an ELISA system. Sera samples (67) for COVID-19 patients, as well as sera samples from healthy volunteers (112), along with sera samples from non-COVID-19 patients were examined by the ELISA system. The expression and purity of the recombinant N protein were approved by SDS-PAGE and Western blotting. The sensitivity of ELISA system was 91.04 and 92.53% for the detection of IgG and IgM antibodies, respectively. Moreover, the specificity of the developed ELISA system for IgG and IgM were 98.21 and 97.32%, respectively. Our developed ELISA system showed satisfactory sensitivity and specificity for the detection of antiSARS-CoV-2 IgM and IgG antibodies and could be used as a complementary approach for proper diagnosis of COVID-19.
| S-EPMC9011413 | biostudies-literature
Project description:The ongoing coronavirus disease 19 (COVID-19) pandemic, caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), poses a threat to human health. Despite this, many affected countries are now in the process of gradual lifting of COVID-19 restrictions that were initially implemented in response to the pandemic. The success of the so-called "exit strategy" requires continued surveillance of virus circulation in the community and evaluation of the prevalence of protective immunity among population. Serology tests are valuable tools for these purposes. Herein, SARS-CoV-2 full-length spike (S) recombinant protein was utilized to develop and optimize an indirect enzyme-linked immunoassay (ELISA) that enables a reliable detection of virus-specific IgG antibody in human sera. Importantly, the performance of this assay was evaluated utilizing micro-neutralization (MN) assay as a reference test. Our developed ELISA offers 100% sensitivity, 98.4% specificity, 98.8% agreement, and high overall accuracy. Moreover, the optical density (OD) values of positive samples significantly correlated with their MN titers. The assay specifically detects human IgG antibodies directed against SARS-CoV-2, but not those to Middle East respiratory syndrome coronavirus (MERS-CoV) or human coronavirus HKU1 (HCoV-HKU1). The availability of this in-house ELISA protocol would be valuable for various diagnostic and epidemiological applications.
| S-EPMC7601663 | biostudies-literature