Value of 2 IgG avidity commercial tests used alone or in association to date toxoplasmosis contamination

• Published in: Diagnostic microbiology and infectious disease Vol. 64; no. 3; pp. 267 - 274
• Main Authors: Lachaud, Laurence, Calas, Olivier, Picot, Marie Christine, Albaba, Sahar, Bourgeois, Nathalie, Pratlong, Francine
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01.07.2009; Elsevier
• Subjects: Antibody Affinity - immunology; Avidity tests; Biological and medical sciences; Comparison; Female; Fundamental and applied biological sciences. Psychology; Human protozoal diseases; Humans; Immunoglobulin G - blood; Immunoglobulin M - blood; Infant, Newborn; Infectious Disease; Infectious diseases; Internal Medicine; Medical sciences; Microbiology; Parasitic diseases; Pregnancy; Pregnant women; Protozoal diseases; Sensitivity and Specificity; Time Factors; Toxoplasmosis; Toxoplasmosis - diagnosis; Avidity tests; Toxoplasmosis; Comparison; Pregnant women; Human; Protozoal disease; Microbiology; IgG; Parasitosis; Contamination; Infection; Avidity; Female
• ISSN: 0732-8893; 1879-0070
• DOI: 10.1016/j.diagmicrobio.2009.02.014

Abstract Toxoplasmosis acquired during pregnancy exposes the fetus to congenital toxoplasmosis. Avidity tests are commonly used to date time of infection to evaluate the fetal risk and to offer prenatal diagnosis. This study evaluated and compared 2 commercial avidity tests: Platelia™ Toxo IgG Avidity (Bio-Rad, Marnes la Coquette, France) and Liaison® Toxo IgG Avidity II (Diasorin, Saluggia, Italy) kits. In complement, a study of specific IgG and IgM in the 2 systems was carried out. Sensitivity and specificity of the avidity tests were 94.4% and 87.8% for the Liaison® and 91.3% and 98.5% for the Platelia™ methods, respectively. Percentages of complete discrepancies, partial discrepancies, and agreement between both tests were 1.1%, 23.6%, and 75.3%, respectively. Moreover, the combination of both avidity tests may be useful in some cases. Indeed, that strategy permitted to confirm without delay a chronic toxoplasmosis in 23 cases and avoid treatment in these pregnant women.