Detection of immunoglobulin G (IgG) and IgM antibodies to Toxoplasma gondii: evaluation of four commercial immunoassay systems

Abstract

A comparative evaluation of the following commercial immunoassays for the determination of antibodies to Toxoplasma gondii was performed: Behring Diagnostics OPUS Toxo G and Toxo M, Abbott Diagnostics IMX Toxo-IgG 2.0 and Toxo-IgM, Sanofi Diagnostics Pasteur Platelia Toxo IgG and Toxo IgM, and bioMérieux Vitek VIDAS Toxo IgG and IgM. Of 676 specimens that were tested for Toxoplasma-specific immunoglobulin G (IgG) antibodies, 26% were reactive by all methods while 8% displayed some discrepancy. Of 718 specimens that were tested for Toxoplasma-specific IgM antibodies, 3% were reactive by all methods while 10% displayed some discrepancy. Analysis of discrepant specimens revealed performance shortcomings with all IgM-specific assays. The impact of such shortcomings is magnified in a population with a low prevalence of toxoplasmosis.

Detection of Toxoplasma Gondii Dna and Specific Antibodies in High-Risk Pregnant Women

“…20 Routine serologic diagnosis of toxoplasmosis provides high sensitivity, but specificity varies depending on the test used, and false-positive IgM antibody test results have been reported by other investigators. 21,22 In addition, even true positive results must be interpreted with caution 23 because IgM antibodies may persist for Ն 1 year after acute infection. 24,25 Diagnosis of primary infection with T. gondii in early pregnancy can be improved by determination of anti-toxoplasma IgG avidity, which has the ability to discriminate between recent and prior infections.…”

Recombinant Antigens To DetectToxoplasma gondii-Specific Immunoglobulin G and Immunoglobulin M in Human Sera by Enzyme Immunoassay

“…Since a number of the serological targets for the detection of T. gondii antibodies are sequestered within internal organelles, the method of preparation of the tachyzoite antigen has a significant effect on assay performance, as shown by the differential agglutination assay (6). Hence, it is not surprising that commercial tests that employ the tachyzoite antigen to detect serum antibodies exhibit interassay variation (14,19,28,29,53,59).…”

“…The enzyme-linked immunosorbent assay (ELISA) for the detection of immunoglobulins is one of the easiest tests to perform, and many manual and automated serologic tests for the detection of T. gondii-specific immunoglobulin G (IgG) and IgM are commercially available. The currently available tests for the detection of IgG and IgM antibodies in infected individuals vary in their ability to detect serum antibodies (14,19,28,29,53,59). The differences observed between these serologic tests is probably due in part to the various preparations of antigen used to detect serum antibody.…”

Differences in onset of disease and severity of psychopathology between toxoplasmosis‐related and toxoplasmosis‐unrelated schizophrenia

“…Our interpretation was that no subject had an acute toxoplasmosis in the course of the study. Distinction between acute and latent toxoplasmosis by IgG ELISA and CFT tests is sometimes difficult, however, detection of IgG Toxoplasma-specific antibodies is rarely problematic, and high sensitivity and specificity have been achieved by a variety of methods (33). The relapse of acute toxoplasmosis in immunosuppressed patients with positive titres of antibodies induced by past Toxoplasma infection suggests that the seropositivity, that is, the presence of specific serum IgG antibodies against Toxoplasma, always indicates the presence of viable parasites.…”