Antibody detection is essential to establish exposure, infection and immunity to SARS-CoV-2, as well as to perform epidemiological studies. The worlwide urge for new diagnostic tools to control the pandemic has led to a quick in- corporation in clinical practice of the recently developed serological assays.
We evaluated the diagnostic accuracy to detect Ig G, Ig M+A and/or IgA anti SARS-CoV-2 of 10 different assays: 3 Lateral Flow card inmunoassays, 4 en- zyme-linked inmunoabsorbent assay (ELISA) and 3 chemiluminescent particle immunoassays (CMIA). Using PCR for COVID-19 as gold standard, sensitivity, specificity, PPV, and NPV were determined. Each assay was tested in 2 groups: Positive Controls, formed by 50 sera from 50 patients with SARS-CoV-2 pneu- monia with positive PCR; Negative Controls, formed by 50 sera from 50 pa- tients with respiratory infection non-COVID-19.
Sensitivity range of the 10 assays evaluated for patients with positive COVID-19 PCR was 40-77% (65-81% considering IgG plus IgM). Specificity ranged 83-100%. VPP and VPN were respectively 81-100% and 61.6-81%.
Results obtained varied widely among the assays evaluated.
Highest diagnostic accuracy was obtained with ELISA and CMIAs, but they last much longer.