Evaluation of ultramicroanalytic assays to detect antibodies against SARS-CoV-2

Abstract

Introduction: This paper shows the results obtained in the validation of in vitro serological assays to detect IgM, IgG antibodies, and total antibodies against SARS-CoV-2 UMELISA SARS-CoV-2 IgM, UMELISA ANTI-SARS-CoV-2 and UMELISA SARS-CoV-2 IgG developed by the Immunoassay Center.

Methods: Panels of serum samples from negative and COVID-19 confirmed patients were used to determine the analytical performance of each assay.

Results: UMELISA SARS-CoV-2 IgM, UMELISA ANTI-SARS-CoV-2 and UMELISA SARS-CoV-2 IgG assays demonstrated 100% clinical specificity for all assays; and 100% analytical specificity for the first two assays, and 93.1% for the last one. Clinical sensitivity was 64.3%, 80.8% and 97.5%, respectively. The positive predictive value was 100% in all assays, while the negative predictive value ranged from 83.3% to 95.2%. Concordance varied from 92.4% to 96.9%, and kappa index in every assay was very good. Assays sensitivity increased to 82.7%, 96.5% and 100 %, respectively for serum samples collected more than 14 days after onset of the symptoms.

Conclusions: The assays demonstrated high sensitivity and specificity, which allows us to have Cuban technology-based tools for serological, epidemiological surveillance, and other types of studies, including those related to vaccines on a platform with wide national distribution.