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Evaluation of a New Immunochromatography Technology Test (LDBio Diagnostics) To Detect Toxoplasma IgG and IgM:
Caroline Mahinc1, Pierre Flori2, Edouard Delaunay3
1Pôle de Biologie-Pathologie, Parasitology and Mycology Laboratory, University Hospital of Saint Etienne, Saint Etienne, France caroline.mahinc@chu-st-etienne.fr.
Insights
The immunochromatography technology (ICT) rapid diagnostic test shows superior sensitivity for Toxoplasma IgG detection compared to automated systems. This ICT test also offers high sensitivity and specificity for Toxoplasma IgM detection.
Area of Science:
- Medical Diagnostics
- Immunology
- Infectious Diseases
Background:
- Toxoplasmosis diagnosis relies on accurate detection of IgG and IgM antibodies.
- Automated systems face limitations in sensitivity for IgG and specificity for IgM detection.
Purpose of the Study:
- To compare the performance of an immunochromatography technology (ICT) rapid diagnostic test against a fully automated Architect system for Toxoplasma IgG and IgM detection.
- To evaluate the sensitivity and specificity of both diagnostic methods.
Main Methods:
- A comparative study involving 767 prospective and 235 selected sera.
- Reference techniques included Toxoplasma IgGII Western blot, Platelia Toxo IgM, and Toxo-ISAgA.
- Sensitivity and specificity were assessed for ICT and Architect IgG and IgM assays.
Main Results:
- ICT demonstrated 100% sensitivity for IgG compared to 92.1% for Architect, especially in low-titer sera.
- ICT showed 98.7% specificity for IgG, while Architect achieved 99.8%.
- For IgM, ICT exhibited 100% sensitivity and 100% specificity, outperforming Architect's 96.1% sensitivity and 99.6% specificity.
Conclusions:
- The ICT rapid diagnostic test offers superior sensitivity for Toxoplasma IgG detection over automated systems.
- ICT provides highly sensitive and specific detection of Toxoplasma IgM, overcoming limitations of automated platforms.
- This ICT test is a valuable tool for accurate Toxoplasmosis diagnosis, particularly for challenging cases.
Abstract:
A study comparing the ICT (immunochromatography technology) Toxoplasma IgG and IgM rapid diagnostic test (LDBio Diagnostics, France) with a fully automated system, Architect, was performed on samples from university hospitals of Marseille and Saint-Etienne. A total of 767 prospective sera and 235 selected sera were collected. The panels were selected to test various IgG and IgM parameters. The reference technique, Toxoplasma IgGII Western blot analysis (LDBio Diagnostics), was used to confirm the IgG results, and commercial kits Platelia Toxo IgM (Bio-Rad) and Toxo-ISAgA (bioMérieux) were used in Saint-Etienne and Marseille, respectively, as the IgM reference techniques. Sensitivity and specificity of the ICT and the Architect IgG assays were compared using a prospective panel. Sensitivity was 100% for the ICT test and 92.1% for Architect (cutoff at 1.6 IU/ml). The low-IgG-titer serum results confirmed that ICT sensitivity was superior to that of Architect. Specificity was 98.7% (ICT) and 99.8% (Architect IgG). The ICT test is also useful for detecting IgM without IgG and is both sensitive (100%) and specific (100%), as it can distinguish nonspecific IgM from specific Toxoplasma IgM. In comparison, IgM sensitivity and specificity on Architect are 96.1% and 99.6%, respectively (cutoff at 0.5 arbitrary units [AU]/ml). To conclude, this new test overcomes the limitations of automated screening techniques, which are not sensitive enough for IgG and lack specificity for IgM (rare IgM false-positive cases).
