Evaluation of Two Chemiluminescent and Three ELISA Immunoassays for the Detection of SARS-CoV-2 IgG Antibodies: Implications for Disease Diagnosis and Patients' Management

• Published in: Frontiers in immunology 2020-12, Vol.11, p.609242-609242
• Main Authors: Speletas, Matthaios, Kyritsi, Maria A, Vontas, Alexandros, Theodoridou, Aikaterini, Chrysanthidis, Theofilos, Hatzianastasiou, Sophia, Petinaki, Efthimia, Hadjichristodoulou, Christos
• Format: Article
• Language: English
• Subjects: Antibodies, Viral - blood; chemiluminescent; COVID-19; COVID-19 - blood; COVID-19 - diagnosis; COVID-19 - epidemiology; COVID-19 - virology; COVID-19 Testing; ELISA; Humans; IgG; Immunoassay; Immunoglobulin G - blood; Immunology; Luminescent Measurements; SARS-CoV-2 - immunology; Sensitivity and Specificity; Seroepidemiologic Studies
• ISSN: 1664-3224; 1664-3224
• DOI: 10.3389/fimmu.2020.609242

The estimation of anti-SARS-CoV-2 IgG antibodies is possibly the best approach to accurately establish the number of infected individuals and the seroprevalence of COVID-19 within a population. Thus, several commercial immunoassays have recently been developed. The purpose of our study was to assess the performance of five commonly used immunoassays in Greece (3 ELISA, namely Euroimmun SARS-CoV-2, GA GENERIC SARS-CoV-2 and Vircell COVID-19; and 2 chemiluminescent, namely ABBOTT SARS-CoV-2 and ROCHE Elecsys Anti-SARS-CoV-2 test) for the detection of anti-SARS-CoV-2 IgG antibodies. Sera specimens derived from 168 individuals were utilized to assess the specificity and sensitivity score of each assay. Among them, we included 99 COVID-19 patients (29 asymptomatic, 36 with symptom onset 4 to 14 days before serum sampling, and 34 with symptom initiation ≥ 15 days ago), and 69 volunteers with sera specimens collected prior to the SARS-CoV-2 outbreak and maintained at -80°C. We demonstrated that chemiluminescent immunoassays exhibit a significantly higher specificity score but a lower sensitivity, compared to ELISA immunoassays. Moreover, immunoassays detecting IgG antibodies against SARS-CoV-2 N protein instead of S protein alone are more reliable, considering both specificity and sensitivity scores. Interestingly, all asymptomatic patients displayed anti-SARS-CoV-2 IgG antibodies, confirmed by at least two immunoassays. We suggest that chemiluminescent assays could be used as screening methods for the detection of anti-SARS-CoV-2 antibodies to evaluate the possible prevalence of disease in the general population, while ELISA assays would be more reliable to evaluate, and follow-up confirmed COVID-19 patients.