Concordance of "rapid" serological tests and IgG and IgM chemiluminescence for SARS-COV-2

Abstract:

Background The COVID-19 serological tests for IgG and IgM have been developed with several methodologies: Immunoenzymatic Assay (ELISA), Chemiluminescence, Electro Chemiluminescence, Fluorescent Lateral Flow Immunoassays and Immunochromatography. None of these tests should be used for the diagnosis or population screening of the disease, considering that the antibodies appear only on the 8th – 14th day of the disease onset. The present study evaluates a sample of immunofluorescent and immunochromatographic rapid tests to show their agreement in relation to Chemiluminescence. Methods A diagnostic test evaluation assay was performed to establish the performance of five “rapid” tests (4 immunochromatographic and 1 immunofluorescent tests) for IgG and IgM serology for SARS-CoV-2 using a panel of 30 serum samples from patients received in the laboratory analysis routine. For the evaluation of clinical performance, the qualitative results of the “rapid” tests were compared against those obtained by chemiluminescence, dichotomized as positives (≥ 10 AU / mL) or negative (<10 UA / mL). Findings The best agreement is seen in the immunofluorescent assay, for the IgG contrast, with a particularly good kappa index (0.85), without positive disagreements and a negative disagreement of about 15%. In the immunochromatographic methods Kappa index was 0.61 at best, with disagreements in negative findings of ≈35% and in positive cases of up to ≈70%. The IgM concordance behavior, on the other hand, reflects a weak to moderate Kappa concordance value (Kappa 0.2 to 0.6), with negative disagreements reaching up …

Año de publicación:

2020

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