Evaluation of two SARS-CoV-2 lateral flow antibody kits for serological diagnosis of COVID-19

Objective: The emergence of new SARS-CoV-2 has prompted the development of new serological tests that could be complementary to RT-PCR. Serological tests can also be used for purposes such as demonstrating the presence of antibodies in individuals who have had the disease, contact screening, screening of healthcare professionals, monitoring of vaccine responses, detection of antibody levels of plasma donors, and determination of seroprevalence in risky groups. For this purpose, different methods such as ELISA, CLIA or rapid antibody detection tests are used. LFIA tests are fast, easy to apply, do not require experience, and are cheap tests that give a result in as little as 10 minutes. However, the clinical performance of existing serological tests used in diagnosis needs to be evaluated. The aim of this study was to assess the performance of two immunological tests for the detection of SARS-CoV-2 antibodies. Methods: As a positive serum panel, 101 serum samples from patients confirmed by SARS-CoV-2 RT-PCR test and also found antibody positive by ELISA test were included in the study. As the negative serum panel, 30 serum samples were determined, including 11 serum samples with antibodies against viruses other than SARS-CoV-2, and 19 serum samples from healthy donors in 2019. First, SARS-CoV-2 antibodies were tested by ELISA (Wantai, China) and than these serum samples were tested simultaneously with the SureScreen COVID-19 IgG/IgM Rapid Test Cassette and YHLO Gline 2019 nCov IgG/IgM kits. Results: The SureScreen and YHLO Gline kits showed an overall sensitivity of 86.1% and 75.3%, for detecting IgG and/or IgM, respectively. Specificity was 100% in both rapid antibody tests. The kappa value for IgG of the two rapid antibody tests was 0.816, while it was 0.695 for IgM. Conclusion: Our study shows that SureScreen and YHLO Gline are reliable kits for use as point-of-care tests for rapid antibody detection. According to Cohen's kappa statistics the 91% (ϰ=0.816) agreement between SureScreen IgG and YHLO Gline IgG, "Almost Perfect”, and 85% agreement (ϰ=0.695) between SureScreen IgM and YHLO Gline IgM, "Substantial”, indicate a good correlation between the performance of the LFIAs used in the study. Total antibody conformity was determined as 92% (ϰ=0.822), "Almost Perfect”. Agreement between IgM tests was lower than that between IgG tests. © 2022,Turk Hijyen ve Deneysel Biyoloji Dergisi,All rights reserved