Contribution of the Toxoplasma ICT IgG IgM^® test in determining the immune status of pregnant women against toxoplasmosis

Abstract

Background An immunochromatography technology (ICT) rapid diagnostic test, the Toxoplasma ICT IgG‐IgM®, was recently developed. Our aim was to study its contribution to establish accurately the Toxoplasma immune status in Tunisian pregnant women using Western blot (WB) Toxo II IgG® as a reference technique. Methods Thirty‐nine sera were selected for the study from among 2,615 which were already tested by IgG and IgM ELISA. They displayed equivocal IgG titres (4.4–9 IU/ml) in absence of IgM (19 sera) or IgM anti‐Toxoplasma antibodies in absence of IgG (titre <4.4 IU/ml) (20 sera). All these sera were additionally tested by WB Toxo II IgG®. Results Immunochromatography technology Sensitivity in the detection either of low IgG titres in absence of IgM or of specific anti‐Toxoplasma IgM was 100%. Only one serum with equivocal IgG titre by ELISA and negative with Toxo II IgG® test revealed positive in ICT. However, this serum showed a P30 band in WB analysis. On the other hand, three sera positive in ELISA IgM and negative in ELISA IgG revealed positive in ICT and negative in WB Toxo II IgG®, the reference test. Conclusion Results confirm the high sensitivity of Toxoplasma ICT IgG‐IgM® in detecting both specific anti‐Toxoplasma IgG and IgM, and highlight the usefulness of this rapid test as a first or second‐line Toxoplasma serological test in pregnant women.