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Aims: The indigenously developed Indian Council of Medical Research (ICMR)-NIV COVID Kavach IgG enzyme linked immunosorbent assay (ELISA) has been recommended for seroprevalence among vulnerable populations in India, which provided essential services throughout the lockdown. The staff working in the High Court was one such group. We compared anti-SARS-CoV-2 IgG seropositivity among the staff of Jodhpur and Jaipur High Courts, Rajasthan, India. Methods: Asymptomatic judiciary staff of Jodhpur and Jaipur benches of High Courts were enrolled after informed written consent. A questionnaire was filled and 3–5 ml venous blood was collected from participants. The ICMR-NIV COVID Kavach IgG ELISA and EUROIMMUN IgG ELISA were used for detection of Anti-SARS-CoV-2 IgG antibodies. Results: A total of 63 samples (41 from Jodhpur and 22 from Jaipur) were collected between 28th July to 4th August 2020. The overall anti-SARS-CoV-2 IgG seroprevalence was found to be 6.35%. Seropositivity was higher among the staff from Jaipur (13.64%) as compared to Jodhpur (2.44%). The Kavach ELISA results were in complete agreement with EUROIMMUN ELISA. The infection control measures were deemed effective. Conclusion: Seroprevalence among the staff of Jodhpur High Court was found to be lower than Jaipur, reflecting higher susceptibility to COVID-19 in the former. Many offices worldwide are closed till mid 2020 but need to come up with pre-emptive policies eventually. This study may help to anticipate the possible challenges when other government/private offices start functioning. The infection control practices of one workplace may help formulate guidelines for other offices.

For diagnosis of neuroborreliosis, calculation of the antibody index, based on Euroimmun Anti-Borrelia plus VlsE ELISA was compared to Virotech Borrelia Europe plus TpN17 immunoblot-based detection of Borrelia-specific intrathecal antibody production. CXCL13 results in cerebrospinal fluid were used to evaluate discordant results. A total of 64 serum/CSF pairs were analysed. Patients were classified according to European Federation of Neurological Societies criteria incorporating Virotech results. For the Euroimmun assay, a sensitivity of 100% and specificity of 94% was found. Agreement between the both tests was almost perfect (κ 0.81). Both methods are appropriate for the detection of Borrelia-specific intrathecal antibody production. [ABSTRACT FROM AUTHOR]

SARS-CoV-2 antibody assays are used for epidemiological studies and for the assessment of vaccine responses in highly vulnerable patients. So far, data on cross-reactivity of SARS-CoV-2 antibody assays is limited. Here, we compared four enzyme-linked immunosorbent assays (ELISAs; Vircell SARS-CoV-2 IgM/IgA and IgG, Euroimmun SARS-CoV-2 IgA and IgG) for detection of anti-SARS-CoV-2 antibodies in 207 patients with COVID-19, 178 patients with serological evidence of different bacterial infections, 107 patients with confirmed viral respiratory disease, and 80 controls from the pre-COVID-19 era. In COVID-19 patients, the assays showed highest sensitivity in week 3 (Vircell-IgM/A and Euroimmun-IgA: 78.9% each) and after week 7 (Vircell-IgG: 97.9%; Euroimmun-IgG: 92.1%). The antibody indices were higher in patients with fatal disease. In general, IgM/IgA assays had only limited or no benefit over IgG assays. In patients with non-SARS-CoV-2 respiratory infections, IgG assays were more specific than IgM/IgA assays, and bacterial infections were associated with more false-positive results than viral infections. The specificities in bacterial and viral infections were 68.0 and 81.3% (Vircell-IgM/IgA), 84.8 and 96.3% (Euroimmun-IgA), 97.8 and 86.0% (Vircell-IgG), and 97.8 and 99.1% (Euroimmun-IgG), respectively. Sera from patients positive for antibodies against Mycoplasma pneumoniae, Chlamydia psittaci, and Legionella pneumophila yielded particularly high rates of unspecific false-positive results in the IgM/IgA assays, which was revealed by applying a highly specific flow-cytometric assay using HEK 293 T cells expressing the SARS-CoV-2 spike protein. Positive results obtained with anti-SARS-CoV-2 IgM/IgA ELISAs require careful interpretation, especially if there is evidence for prior bacterial respiratory infections. [ABSTRACT FROM AUTHOR]

Aims: The indigenously developed Indian Council of Medical Research (ICMR)-NIV COVID Kavach IgG enzyme linked immunosorbent assay (ELISA) has been recommended for seroprevalence among vulnerable populations in India, which provided essential services throughout the lockdown. The staff working in the High Court was one such group. We compared anti-SARS-CoV-2 IgG seropositivity among the staff of Jodhpur and Jaipur High Courts, Rajasthan, India. Methods: Asymptomatic judiciary staff of Jodhpur and Jaipur benches of High Courts were enrolled after informed written consent. A questionnaire was filled and 3--5 ml venous blood was collected from participants. The ICMR-NIV COVID Kavach IgG ELISA and EUROIMMUN IgG ELISA were used for detection of Anti-SARS-CoV-2 IgG antibodies. Results: A total of 63 samples (41 from Jodhpur and 22 from Jaipur) were collected between 28th July to 4th August 2020. The overall anti-SARS-CoV-2 IgG seroprevalence was found to be 6.35%. Seropositivity was higher among the staff from Jaipur (13.64%) as compared to Jodhpur (2.44%). The Kavach ELISA results were in complete agreement with EUROIMMUN ELISA. The infection control measures were deemed effective. Conclusion: Seroprevalence among the staff of Jodhpur High Court was found to be lower than Jaipur, reflecting higher susceptibility to COVID-19 in the former. Many offices worldwide are closed till mid 2020 but need to come up with pre-emptive policies eventually. This study may help to anticipate the possible challenges when other government/private offices start functioning. The infection control practices of one workplace may help formulate guidelines for other offices. [ABSTRACT FROM AUTHOR]

Since December 2019, we have been in the battlefield with a new threat to the humanity, known as severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2), which causes coronavirus disease 2019 (COVID‐19), characterized by viral pneumonia. It may be asymptomatic or cause various symptoms, ranging from flu‐like symptoms to acute respiratory distress syndrome and eventually death. At present, the only reliable test for COVID‐19 diagnosis is quantitative reverse transcriptase‐polymerase chain reaction. Assessing the immune response against SARS‐CoV‐2 could increase the detection sensitivity of infected population. Hereby, we report the performances of a fully automated chemiluminescent immunoassay (CLIA) on 276 serum samples. One hundred samples obtained from COVID‐19 negative subjects (COVID‐19 free) were analyzed to evaluate the diagnostic specificity of antibody (Ab) detection. Thereafter, 176 samples obtained from 125 patients with confirmed COVID‐19 (COVID‐19 patients) were selected to assess the diagnostic sensitivity of the CLIA. All samples were analyzed on MAGLUMI 800 platform. All COVID‐19 free samples had Ab levels below the cutoff values. Hence, the diagnostic specificity was estimated at 100% (95% confidence interval [CI] = 96.3‐100.0; positive predictive value = 100%). By the 18th day from the onset of symptoms, we reached an optimal diagnostic sensitivity (more than 95.0%) In fact, the diagnostic sensitivity increased over time and between 15 and 25 days after symptoms onset, reached 95.5% (95% CI = 84.9‐99.2). The new automated CLIA analyzer appeared to be a robust and reliable method to measure specific Ab against COVID‐19 at high throughput. Our data suggest that combining Ab and nucleic acid detection could increase diagnostic sensitivity. Highlights: In this manuscipt we showed, measuring Antibodies (ABs) against COVID‐19 can increase the sensitivity of the detection of infected population. Clinically false negative results could be expected in the early stages of infection, but clinically false positive results appeared to be rare. The age and early deaths were negatively related to Ab development. However, the time from symptoms onset to sampling, and to hospital admission, were positively related to Ab development. The CLIA method appeared to be reliable to measure Abs against COVID‐19 at a high throughput. [ABSTRACT FROM AUTHOR]

• Anti-SARS-CoV-2 IgG specificity is critical for Covid-19 spread and prevalence studies. • A large collection of pre-pandemic samples is necessary for the assessment of assay specificity. • Specificity of Abbott Architect anti-SARS-CoV-2 IgG assay is high. • Sensitivity of both anti-SARS-CoV-2 IgG assays evaluated are high. We report our findings of test performance especially specificity of a fully automated Abbott Architect anti-SARS-CoV-2 CMIA IgG and Euroimmun anti-SARS-CoV-2 ELISA IgA/IgG in human plasma. We used positive cohort of 97 samples from Covid-19 patients or healthcare workers, collected at late time points from symptom onsets. We also included another cohort of 215 samples as negative controls, 78 of which had positive serology test results of other infectious diseases or autoimmunity. Assay specificity was assessed by using a total of 847 anonymized samples which were collected before the Covid-19 pandemic from local patient populations seeking clinical care for rheumatoid diseases, thyroid cancer, and therapeutic drug monitoring. Abbott IgG, Euroimmun IgG/IgA had high precision, demonstrated by both intra- and inter-day CVs of <2%. There was no Abbott or Euroimmun IgG assay cross reactivity in the 78 samples with positive serology of non-SARS-CoV-2 infectious diseases and positive autoimmune antibodies. The Abbott IgG has specificity of 99.6%, while Euroimmun IgG and IgA were as high as 91.5% and 71.5%, respectively. Our evaluation confirmed high specificity of the Abbott IgG assay, while it was lower for Euroimmun IgG. Euroimmun IgA has suboptimal specificity which may limit its clinical use. Assay sensitivity was high for both Abbott and Euroimmun IgG assays. [ABSTRACT FROM AUTHOR]

Purpose: To assess the diagnostic performances of five automated anti-SARS-CoV-2 immunoassays, Epitope (N), Diasorin (S1/S2), Euroimmun (S1), Roche N (N), and Roche S (S-RBD), and to provide a testing strategy based on pre-test probability. Methods: We assessed the receiver operating characteristic (ROC) areas under the curve (AUC) values, along with the sensitivity, specificity, positive predictive values (PPVs), and negative predictive values (NPVs), of each assay using a validation sample set of 172 COVID-19 sera and 185 negative controls against a validated S1-immunofluorescence as a reference method. The three assays displaying the highest AUCs were selected for further serodetection of 2033 sera of a large population-based cohort. Results: In the validation analysis (pre-test probability: 48.1%), Roche N, Roche S and Euroimmun showed the highest discriminant accuracy (AUCs: 0.99, 0.98, and 0.98) with PPVs and NPVs above 96% and 94%, respectively. In the population-based cohort (pre-test probability: 6.2%) these three assays displayed AUCs above 0.97 and PPVs and NPVs above 90.5% and 99.4%, respectively. A sequential strategy using an anti-S assay as screening test and an anti-N as confirmatory assays resulted in a 96.7% PPV and 99.5% NPV, respectively. Conclusions: Euroimmun and both Roche assays performed equally well in high pre-test probability settings. At a lower prevalence, sequentially combining anti-S and anti-N assays resulted in the optimal trade-off between diagnostic performances and operational considerations.

• Three nonautomated enzyme immunoassays for parvovirus B19 were compared. • IgG and IgM immunoassays from Biotrin, Euroimmun and Serion were compared. • Sensitivity, specificity, and concordance in 195 serum samples were calculated. • Agreement was obtained for 88.7% (IgG) and 75.9% (IgM) results. • Clinical interpretation by all three assays was identical in 83% of the samples. Diagnosis of parvovirus B19 (B19) infection in small-medium size clinical laboratories is most often done by nonautomated enzyme immunoassays (EIAs). Using 195 specimens we compared the analytical performance of Biotrin (Dublin, Ireland), Euroimmun (Lubeck, Germany), and Serion (Würzburg, Germany) EIAs. Sensitivity, specificity, and concordance to Biotrin assay were calculated. Overall complete agreement in the IgG and IgM results was 88.7% (173/195) and 75.9% (148/195) samples, respectively. When equivocal results were considered positive, Serion and Euroimmun highly agreed (>93.8%) with Biotrin in the IgG serology. Serion had better IgM sensitivity and specificity than Euroimmun when compared to Biotrin, although more Serion IgM equivocal results needed reflex testing. Clinical interpretation by all three assays was identical in 83% of the samples. We concluded that overall the performance of these assays was similar and both Serion and Euroimmun could be a suitable replacement for the Biotrin. [ABSTRACT FROM AUTHOR]

Background: Echinococcus granulosus causes human cystic echinococcusis (hydatid cyst) as an important public health problem in many regions of the world. Serologic tests are the main methods for diagnosis of the disease nowadays and enzyme-linked immunosorbent assay (ELISA) is the most routine and common method for diagnosis. There are some problems in primary diagnosis such as cross-reaction with sera from patients with other parasitic disease in serological tests. Using an appropriate source of antigenic material is a very important and crucial point in improvement of ELISA method. Methods: Recombinant AgB Echinococcus granulosus were applied as a new antigen in ELISA and sensitivity and specificity of new kit were compared with Euroimmun hydatid kit. 73 sera from patients with hydatid cyst (confirmed by surgical operation) and 73 healthy individuals' sera were tested by recombinant AgB kit. Findings: The sensitivity of 100% and specificity of 97.33% were determined by homemade kit. Conclusion: According to our results, recombinant EgAgB has good performance in total IgG ELISA for detection of sera antibodies from patients with hydatid cyst. [ABSTRACT FROM AUTHOR]

Purpose: To assess the diagnostic performances of five automated anti-SARS-CoV-2 immunoassays, Epitope (N), Diasorin (S1/S2), Euroimmun (S1), Roche N (N), and Roche S (S-RBD), and to provide a testing strategy based on pre-test probability. Methods: We assessed the receiver operating characteristic (ROC) areas under the curve (AUC) values, along with the sensitivity, specificity, positive predictive values (PPVs), and negative predictive values (NPVs), of each assay using a validation sample set of 172 COVID-19 sera and 185 negative controls against a validated S1-immunofluorescence as a reference method. The three assays displaying the highest AUCs were selected for further serodetection of 2033 sera of a large population-based cohort. Results: In the validation analysis (pre-test probability: 48.1%), Roche N, Roche S and Euroimmun showed the highest discriminant accuracy (AUCs: 0.99, 0.98, and 0.98) with PPVs and NPVs above 96% and 94%, respectively. In the population-based cohort (pre-test probability: 6.2%) these three assays displayed AUCs above 0.97 and PPVs and NPVs above 90.5% and 99.4%, respectively. A sequential strategy using an anti-S assay as screening test and an anti-N as confirmatory assays resulted in a 96.7% PPV and 99.5% NPV, respectively. Conclusions: Euroimmun and both Roche assays performed equally well in high pre-test probability settings. At a lower prevalence, sequentially combining anti-S and anti-N assays resulted in the optimal trade-off between diagnostic performances and operational considerations. [ABSTRACT FROM AUTHOR]