Open AccessReliability of low‐avidity IgG and of IgA in the diagnosis of primary infection by rubella virus with adaptation of a commercial test
Author(s) -
Gutiérrez J.,
Rodríguez M.J.,
De Ory F.,
Piédrola G.,
Maroto M.C.
Publication year - 1999
Publication title -
journal of clinical laboratory analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.536
H-Index - 50
eISSN - 1098-2825
pISSN - 0887-8013
DOI - 10.1002/(sici)1098-2825(1999)13:1<1::aid-jcla1>3.0.co;2-z
Subject(s) - avidity , rubella virus , immunology , antibody , rubella , immunoglobulin g , medicine , virology , virus , vaccination , measles
The detection of IgA and low‐avidity IgG and antibodies in serum is a potentially useful marker of recent infection by a microorganism. We studied the reliability of IgG avidity and presence of IgA for the diagnosis of recent acute infection by rubella virus. Low‐avidity IgG (Avy‐EIA test) was determined with a modified commercial test using 8 molar urea (indirect ELISA, DiaSorin, Italy) and IgA was determined with a homemade indirect ELISA test. Twenty‐five patients with recent primary infection by rubella virus (group I) and 50 healthy subjects (group II) were studied. In group I low‐avidity IgG varied between 100 and 0% (67.3 ± 21.8%); IgA was present in 24 patients (96%). In group II low‐avidity IgG varied from 50.4 to 0% (19.8 ± 16.9%). IgA was present in 2 subjects (4%). The sensitivity of the Avi‐EIA and the IgA test was 92 and 96%, respectively; specificity was 100 and 96%, respectively. We conclude that both low‐avidity IgG and IgA tests are helpful and reliable for the diagnosis of recent primary infection. J. Clin. Lab. Anal. 13:1–4, 1999. © 1999 Wiley‐Liss, Inc.