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Qualitative assessment of SARS‐CoV‐2‐specific antibody avidity by lateral flow immunochromatographic IgG/IgM antibody assay
Author(s) -
Valdivia Arantxa,
Torres Ignacio,
Huntley Dixie,
Alcaraz María J.,
Albert Eliseo,
Colomina Javier,
Ferrer Josep,
Carratalá Arturo,
Navarro David
Publication year - 2021
Publication title -
journal of medical virology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 121
eISSN - 1096-9071
pISSN - 0146-6615
DOI - 10.1002/jmv.26344
Subject(s) - avidity , antibody , covid-19 , virology , immunology , immunoglobulin g , immunoglobulin m , medicine , pathology , disease , infectious disease (medical specialty)
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.