Evaluation of a New Immunochromatography Technology Test (LDBio Diagnostics) To Detect Toxoplasma IgG and IgM: Comparison with the Routine Architect Technique

Abstract

A study comparing the ICT (immunochromatography technology) 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, 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 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).

Global initiative for congenital toxoplasmosis: an observational and international comparative clinical analysis

“…Different countries set their own healthcare priorities. Robust point-of-care testing, with high sensitivity and specificity and low costs, along with multiplexed testing for other congenital infections that are also treatable, including syphilis, hepatitis B, and HIV, currently in development, will further facilitate screening programs 70 , 82 , 83 . These measures will save lives, prevent expenditures, and reduce suffering, in addition to providing substantial spillover benefits for maternal, child, and family health 70 .…”

“…The cost to developing countries will continue to increase if cases continue to increase and robust public health interventions are not implemented. Robust point-of-care testing with high sensitivity and specificity and low costs exists or is in development 70 , 82 , 83 . In between first trimester and end-of-gestation testing, Toxoplasma serology can be checked with newly developed, rapid POC tests, which are tractable, easy to use, and economical.…”

“…In between first trimester and end-of-gestation testing, Toxoplasma serology can be checked with newly developed, rapid POC tests, which are tractable, easy to use, and economical. It has been demonstrated that an LDBIO POC test, developed in France, is highly sensitive, specific, and low cost at $8 USD per test 70 , 82 , 83 . Additionally, new testing is in development to evaluate the role of testing saliva and whole blood, which will continue to revolutionize testing and make it more readily available for patients.…”

Serological and molecular rapid diagnostic tests for Toxoplasma infection in humans and animals

“…Since the LDBIO test demonstrated 100% sensitivity and exhibited negligible false-positive results, it is advantageous for universal screening of Toxoplasma infection [35]. In short, the LDBIO POC test addresses the limitations of automated screening methods, i.e., not sufficiently sensitive for IgG detection and lack of specificity for IgM detection [42].…”

Evaluation of Three Point-of-Care Tests for Detection of Toxoplasma Immunoglobulin IgG and IgM in the United States: Proof of Concept and Challenges

“…Point-of-care technology for antibody detection usually consists of immunochromatographic (ICT) membrane-based assays that can be performed without sophisticated laboratory infrastructure. Previous studies have shown optimal diagnostic performance for the Toxoplasma ICT IgG-IgM (LDBIO Diagnostics, Lyon, France) POC kit when compared with reference-serological methods in France [ 29 , 30 ] and the United States [ 31 ]. However, direct comparisons of performance of various POC kits against reference-standard methods used in the United States, where T gondii strains are more diverse, have not been previously performed.…”