Specificity testing by point prevalence as a simple assessment strategy using the Roche Elecsys® anti-SARS-CoV-2 immunoassay

Abstract

Background The detection of antibodies against the novel coronavirus 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 of these assays have been launched by various manufacturers. Unfortunately, the new FDA emergency use regulations have resulted in a situation where laboratories have to perform their own validation studies. Numerous of these labs do not have the biobank needed to carry the studies out. Methods In this paper, we introduce a method that allows institutions to quickly perform a verifiation study in a low-prevalence infection situation. As proof of concept, we used the Roche Elecsys Anti-SARS-CoV-2 ECLIA assay and an SAP-based hospital information system. The Shenzhen YHLO Biotech IgM and IgG assay targetting other surface patterns, was used as confirmatory test. Results The Roche assay demonstrated a limit of detection of 0.069 COI (cutoff index) and successfully passed the performance validation according to CLSI EP15-A3. The study population of 627 in-patients exhibited an age median of 64 years and approximately 13% of the group were under intensive care at the respective time point. All included patients were tested negative for SARS-CoV-2 infection by qRT-PCR (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. Using the chosen approach, it was shown that the Roche test achieved very good results in terms of diagnostic specificity, reproducibility and limit of detection.

Persistence of Anti-SARS-CoV-2 Antibodies Six Months after Infection in an Outbreak with Five Hundred COVID-19 Cases in Borriana (Spain): A Prospective Cohort Study

“…Many serologic tests of SARS-CoV-2 measure IgA, IgG and IgM, with high heterogeneity in sensitivity and specificity [48]. The ECLIA technique has a good accuracy [3,49,50] and has been recommended for population screening [51]. Anti-SARS-CoV-2 antibodies obtained by ECLIA positively correlate with neutralising antibodies, but their sensitivity should be improved [52,53].…”

Medium‐term serostatus in Spanish case series recovered from SARS‐CoV‐2 infection

“…As it takes place in a clinical setting, a complementary independent confirmatory test addressing different surface antigens was not performed. The sensitivity of the Elecsys Anti‐SARS‐CoV‐2 in clinical practice differs from manufacturer data, keeping high overall diagnostic sensitivity and specificity, which range from 68.8% to 97.2% and from 99.05% to 100%, respectively 19 …”

“…The sensitivity of the Elecsys Anti‐SARS‐CoV‐2 in clinical practice differs from manufacturer data, keeping high overall diagnostic sensitivity and specificity, which range from 68.8% to 97.2% and from 99.05% to 100%, respectively. 19 As we lack a sequence of repeat serologic studies, we cannot determine for sure whether the non‐seroconversion rates in patients with infections of varying severity were due to lack of antibody activation, with low‐level N protein expression and N antibodies production, or to their rapid decline.…”

Persistence of Anti-SARS-CoV-2 Antibodies Six Months After Infection in an Outbreak With Five Hundred COVID-19 Cases in Borriana (Spain): A Prospective Cohort Study

“…Many serologic tests of SARS-CoV-2 measure IgA, IgG, and IgM, with a high heterogeneity in sensitivity and specificity [48]. The ECLIA technique has a good accuracy [3,[49][50] and has been recommended for population screening [51]. Anti-SARS-CoV-2 antibodies obtained by ECLIA positively correlate with neutralising antibodies, but their sensitivity should be improved [52][53].…”