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. 2020 Dec:511:28-32.
doi: 10.1016/j.cca.2020.09.033. Epub 2020 Sep 28.

SARS-CoV-2 infection serology validation of different methods: Usefulness of IgA in the early phase of infection

Massimo Pieri  1 , Marco Ciotti  2 , Nicoletta Carlozzi  3 , Maria Loredana Frassanito  3 , Arianna Meloni  3 , Alessandro Cistera  3 , Giordano Turchetti  3 , Silvia Niscola  3 , Giuseppe Labate  3 , Graziella Calugi  3 , Sergio Bernardini  4
Affiliations

SARS-CoV-2 infection serology validation of different methods: Usefulness of IgA in the early phase of infection

Massimo Pieri et al. Clin Chim Acta. 2020 Dec.

Abstract

Background and aims: A novel coronavirus (SARS-CoV-2) was isolated from the respiratory samples of patients with pneumonia as showed by the sequence analysis of the virus genomes obtained in Wuhan, China. The antibody response to SARS-CoV-2 is not well understood yet, but the availability of sensitive and specific serological assays will be crucial for the early diagnosis of infection, for epidemiological studies and for defining the presence of neutralizing antibodies in response to a possible vaccine.

Materials and methods: We tested and compared the performances of one chemiluminescent immunoassay (CLIA), two enzyme-linked immunosorbent assay (ELISA) and an electrochemiluminescence immunoassay (ECLIA).

Results: The ECLIA serological assay performed best and may be a valid screening method for SARS-COV-2 infection. The IgA detected by the ELISA assay might be a more reliable and stable early serological marker than IgM. Instead, IgGs, as expected, showed stable level after 10 days from symptoms onset.

Conclusion: The ECLIA method could be used as screening test, considering both the excellent performance and the cost per single test; while ELISA assay for IgG and IgA, which are present at a higher level than IgM and last longer, might be used as confirmatory test.

Keywords: CLIA assay; Covid-19 serological test; ECLIA assay; ELISA assay; SARS-CoV-2.

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Conflict of interest statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Figures

Fig. 1
Fig. 1
Kinetcs of IgA (A), IgM (B) and IgG (C) from the symptoms onset in the 40 study patients. Different time frames are shown. Mean and standard deviations are plotted. Dashed-dotted line represent the cut-off value.
See this image and copyright information in PMC

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