title: Analytical validation of anti-toxoplasma IgG immunoassays.
abstract: There are often discrepancies when using different methods to measure anti-Toxoplasma gondii IgG levels in patient samples. The diagnostic performance of a chemiluminescent immunoassay (CLIA) and an enzyme-linked fluorescent assay (ELFA) used as confirmatory tests for samples identified as positive or equivocal by an electrochemiluminescent immunoassay (ECLIA) were examined. Cut-off values were those stated by the manufacturer, and Western blot was used to confirm the results of all methods. All samples identified as positive by ECLIA (n=93) were confirmed as positive by Western blot, as were 14 of the 28 samples identified as equivocal. When these 121 samples were retested, the sensitivities of CLIA and ELFA were 64.4% and 73.8%, respectively. Both methods exhibited a specificity of 100%. This study confirms that the results obtained from the different immunoassays are not comparable, and neither CLIA nor ELFA should be used to confirm ECLIA results, which should instead be confirmed by methods such as Western blot or Sabin-Feldman dye test.
authors.affiliation: Instituto Hermes Pardini, Av. do Contorno 3825,Belo Horizonte, MG, Brazil. guenaelfreire@gmail.com
authors.forename: Guenael Freire de
authors.initials: GF
authors.lastname: Souza
authors.forename: Darlene
authors.initials: D
authors.lastname: Carvalho
authors.forename: William
authors.initials: W
authors.lastname: Pedrosa
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Franck
authors.forename: Renaud
authors.initials: R
authors.lastname: Piarroux
mesh_terms: D000888:Antibodies, Anti-Idiotypic / Q000097:blood*; D000913:Antibodies, Protozoan / Q000097:blood*; D015153:Blotting, Western; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology*; D008163:Luminescent Measurements / Q000379:methods; D012680:Sensitivity and Specificity; D014122:Toxoplasma / Q000276:immunology*; D014123:Toxoplasmosis / Q000175:diagnosis* / Q000276:immunology
chemical_list: D000888:Antibodies, Anti-Idiotypic; D000913:Antibodies, Protozoan; D007074:Immunoglobulin G; C048844:anti-IgG