Search

Background: The detection of antibodies to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is mandatory for the diagnosis, retrospective assessment of disease progression, and correct evaluation of the current infection situation in the population. Many such assays have been launched by various manufacturers. Unfortunately, the new US Food and Drug Administration emergency use regulations have resulted in a situation where laboratories have to perform their own validation studies but many of these laboratories do not have the biobank needed to conduct the studies. Methods: We introduce a method that allows institutions to quickly perform a verification study in a low-prevalence infection situation. As proof of concept, we used the Roche Elecsys® anti-SARS-CoV-2 electrochemiluminescence immunoassay and an SAP-based hospital information system. The Shenzhen YHLO Biotech IgM and IgG assay targeting other surface patterns was used as a confirmatory test. Results: The Roche assay demonstrated a limit of detection of 0.069 cutoff index and successfully passed the performance validation according to Clinical and Laboratory Standards Institute EP15-A3. The study population of 627 inpatients has a median age of 64 years, and approximately 13% of the group were under intensive care at the respective time point. All patients included tested negative for SARS-CoV-2 infection by quantitative reverse transcription polymerase chain reaction (cobas® 6800, Roche, Mannheim, Germany). Only one false-positive result was obtained, resulting in a specificity for the Roche Elecsys anti-SARS-CoV-2 test of 99.84% and a negative predictive value of 99.98%. Conclusions: The anonymized use of residual material enables quick evaluation of anti-SARS-CoV-2 immunoassays, as shown in this work with the Roche Elecsys assay. Comparison of the control population with economic data makes it possible to validate the sampling set and therefore to determine diagnostic specificity. By use of the approach chosen, it was shown that the Roche test achieved very good results in terms of diagnostic specificity, reproducibility, and limit of detection.

• Fast and reliable approach to validate serological tests based on a representative patient population. • Biobank-independent approach. • Roche Elecsys® anti-SARS-CoV-2 assay: specificity of 99.84% and negative predictive value of 99.98%. • Internal validity verification with socioeconomic characteristics from the hospital information system. The detection of antibodies to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is mandatory for the diagnosis, retrospective assessment of disease progression, and correct evaluation of the current infection situation in the population. Many such assays have been launched by various manufacturers. Unfortunately, the new US Food and Drug Administration emergency use regulations have resulted in a situation where laboratories have to perform their own validation studies but many of these laboratories do not have the biobank needed to conduct the studies. We introduce a method that allows institutions to quickly perform a verification study in a low-prevalence infection situation. As proof of concept, we used the Roche Elecsys® anti-SARS-CoV-2 electrochemiluminescence immunoassay and an SAP-based hospital information system. The Shenzhen YHLO Biotech IgM and IgG assay targeting other surface patterns was used as a confirmatory test. The Roche assay demonstrated a limit of detection of 0.069 cutoff index and successfully passed the performance validation according to Clinical and Laboratory Standards Institute EP15-A3. The study population of 627 inpatients has a median age of 64 years, and approximately 13% of the group were under intensive care at the respective time point. All patients included tested negative for SARS-CoV-2 infection by quantitative reverse transcription polymerase chain reaction (cobas® 6800, Roche, Mannheim, Germany). Only one false-positive result was obtained, resulting in a specificity for the Roche Elecsys anti-SARS-CoV-2 test of 99.84% and a negative predictive value of 99.98%. The anonymized use of residual material enables quick evaluation of anti-SARS-CoV-2 immunoassays, as shown in this work with the Roche Elecsys assay. Comparison of the control population with economic data makes it possible to validate the sampling set and therefore to determine diagnostic specificity. By use of the approach chosen, it was shown that the Roche test achieved very good results in terms of diagnostic specificity, reproducibility, and limit of detection. [ABSTRACT FROM AUTHOR]

Summary: Objective: The hepatitis E virus (HEV) is a leading cause of acute hepatitis in developing countries and an emerging pathogen in Europe. HEV seroprevalence has rarely been assessed in cohorts of travelers, and previous studies have reported a very low rate of exposure. We assessed HEV seroprevalence in French expatriate workers. Methods: The prevalence of HEV IgG and IgM was assessed among 43 French expatriate workers using two commercial microplate enzyme immunoassays (Adaltis and Wantai). Additionally HEV IgG-positive sera were tested with an immunoblot assay (recomLine), while IgM-positive sera were tested with a rapid immunochromatographic assay (Assure). Results: The prevalence of anti-HEV IgG was 3.7 times higher in French expatriates than in comparable blood donors from the same area. A discrepancy was evidenced between the HEV IgG results obtained by the Wantai and Adaltis assays (48.8% vs. 30.2%). Conclusions: Expatriation from France, including to areas not recognized as hyperendemic for HEV, may expose individuals to HEV infection. This issue warrants further study; in particular, serology should be compared before and after travel. The most sensitive Wantai serological assay should be used for epidemiological studies to obtain better insight into the epidemiology of HEV. [Copyright &y& Elsevier]