title: Comparative evaluation of the ARCHITECT Toxo IgG, IgM, and IgG Avidity assays for anti-Toxoplasma antibodies detection in pregnant women sera.
abstract: We assessed the performance of the ARCHITECT Toxo IgG, IgM, and IgG Avidity assays against corresponding assays on AxSYM and Vidas using 730 sera from pregnant women. The ARCHITECT Toxo IgG and IgM assays showed a relative sensitivity of 97.5% and 89.9% and a relative specificity of 99.1% and 99.8%, respectively. If IgM sensitivity is calculated only for sera drawn less than 4 months after infection, the relative sensitivity rises to 98.1%. Correlation between the ARCHITECT and Vidas Avidity assays was 0.87 (n = 103). Testing 86 IgG-positive specimens from recent infection (<4 months), we never obtained high avidity results, but 2 specimens were in the gray zone, whereas sera from past infections (>4 months) exhibited high avidity results in 72.5% (137/189) of cases. The method can be used reliably to exclude recent infections in sera with concurrently positive results for IgM and IgG (IgG, >3 IU/mL).
authors.affiliation: Laboratoire de Parasitologie-Mycologie, Institut de Biologie, CHU de Nantes, 44093 Nantes Cedex 1, France. francoise.gay-andrieu@chu-nantes.fr
authors.forename: Françoise
authors.initials: F
authors.lastname: Gay-Andrieu
authors.forename: Hélène
authors.initials: H
authors.lastname: Fricker-Hidalgo
authors.forename: Eva
authors.initials: E
authors.lastname: Sickinger
authors.forename: Anne
authors.initials: A
authors.lastname: Espern
authors.forename: Marie-Pierre
authors.initials: MP
authors.lastname: Brenier-Pinchart
authors.forename: Hans-Bertram
authors.initials: HB
authors.lastname: Braun
authors.forename: Hervé
authors.initials: H
authors.lastname: Pelloux
mesh_terms: D000913:Antibodies, Protozoan / Q000097:blood / Q000276:immunology*; D000915:Antibody Affinity; D057205:Automation, Laboratory / Q000379:methods; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D007074:Immunoglobulin G / Q000097:blood / Q000276:immunology*; D007075:Immunoglobulin M / Q000097:blood / Q000276:immunology*; D011247:Pregnancy; D015597:Pregnancy Complications, Parasitic / Q000097:blood / Q000175:diagnosis* / Q000276:immunology / Q000469:parasitology; D012016:Reference Values; D012680:Sensitivity and Specificity; D014122:Toxoplasma / Q000276:immunology / Q000302:isolation & purification*; D014123:Toxoplasmosis / Q000175:diagnosis* / Q000276:immunology
chemical_list: D000913:Antibodies, Protozoan; D007074:Immunoglobulin G; D007075:Immunoglobulin M