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. 2021 Feb;93(2):1141-1144.
doi: 10.1002/jmv.26344. Epub 2020 Aug 2.

Qualitative assessment of SARS-CoV-2-specific antibody avidity by lateral flow immunochromatographic IgG/IgM antibody assay

Arantxa Valdivia  1 , Ignacio Torres  1 , Dixie Huntley  1 , María J Alcaraz  1 , Eliseo Albert  1 , Javier Colomina  1 , Josep Ferrer  1 , Arturo Carratalá  2 , David Navarro  1   3
Affiliations

Qualitative assessment of SARS-CoV-2-specific antibody avidity by lateral flow immunochromatographic IgG/IgM antibody assay

Arantxa Valdivia et al. J Med Virol. 2021 Feb.

Abstract

Knowledge of the precise timing of SARS-CoV-2 infection may be of clinical and epidemiological relevance. The presence of low-avidity IgGs has conventionally been considered an indicator of recent infection. Here, we carried out qualitative assessment of SARS-CoV-2-specific antibody avidity using an urea (6M) dissociation test performed on a lateral flow immunochromatographic IgG/IgM device. We included a total of 76 serum specimens collected from 57 COVID-19 patients, of which 39 tested positive for both IgG and IgM and 37 only for IgG. Sera losing IgG reactivity after urea treatment (n = 28) were drawn significantly earlier (P = .04) after onset of symptoms than those which preserved it (n = 48). This assay may be helpful to estimate the time of acquisition of infection in patients with mild to severe COVID-19.

Keywords: Covid-19; SARS-CoV-2; antibodies; avidity; urea dissociation.

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Conflict of interest statement

The authors declare no conflicts of interest.

References

    1. Laboratory testing strategy recommendations for COVID‐19: interim guidance. WHO/2019‐nCoV/lab_testing/2020.1.
    1. Arevalo‐Rodriguez I, Buitrago‐Garcia D, Simancas‐Racines D, et al. False‐negative results of initial RT‐PCR assays for Covid‐19: a systematic review. MedRxiv preprint. 2020. 10.1101/2020.04.16.20066787 - DOI - PMC - PubMed
    1. Özçürümez MK, Ambrosch A, Frey O, et al. SARS‐CoV‐2 antibody testing‐questions to be asked. J Allergy Clin Immunol. 2020;146:35‐43. - PMC - PubMed
    1. To KKW, Tsang OTY, Leung WS, et al. Temporal profiles of viral load in posterior oropharyngeal saliva samples and serum antibody responses during infection by SARS‐CoV‐2: an observational cohort study. Lancet Infect Dis. 2020;20:565‐574. - PMC - PubMed
    1. Wölfel R, Corman VM, Guggemos W, et al. Virological assessment of hospitalized patients with COVID‐2019. Nature. 2020;581:465‐469. - PubMed