Bicentric Evaluation of Six Anti-Toxoplasma Immunoglobulin G (IgG) Automated Immunoassays and Comparison to the Toxo II IgG Western Blot

Maudry, Arnaud; Chêne, Geneviève; Chatelain, R; Patural, Hugues; Bellete, B.; Tisseur, Bernard; Hafid, Jamal; Rabérin, H.; Beretta, Sophie; Sung, R. Tran Manh; Belot, Georges; Flori, Pierre

doi:10.1128/cvi.00128-09

Cited by 32 publications

(21 citation statements)

References 16 publications

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“…The current-generation Immulite 2000 TORCH assays show performance that is similar to (13,(28)(29)(30)(31)(32) or better than (4) those previously reported in comparative studies, as well as being similar to the performance of the ETI-MAX assays commonly used in our laboratory, confirming that these assays are suitable for routine prenatal screening. In the case of IgM positivity, however, the IgG avidity test is still mandatory for discriminating between primary infection occurring before and early in pregnancy.…”

supporting

confidence: 82%

Performance Characteristics of Current-Generation Immulite 2000 TORCH Assays

Centonze

Tonolli

Fontana

2013

Clin Vaccine Immunol

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The performances of seven Immulite 2000 (Siemens Healthcare Diagnostics) TORCH (Toxoplasma gondii, other microorganisms, rubella virus, cytomegalovirus, and herpes simplex virus) assays were evaluated in comparison with the performances of the ETI-MAX 3000 (DiaSorin) TORCH assays. The two systems demonstrated good agreement, and given their sensitivity, specificity, and positive predictive value, they can be used with confidence for TORCH prenatal screening. Congenitally acquired infections can result in serious and debilitating sequelae. Prenatal screening for antibodies to the TORCH complex-Toxoplasma gondii, other microorganisms (e.g., Treponema pallidum), rubella virus (RV), cytomegalovirus (CMV), and herpes simplex virus (HSV)-is an important tool for identifying susceptible women, especially those with acute maternal infection, for whom early treatment is essential. Discriminating between primary and recurrent infection also is very important but often difficult (1-3).To facilitate the large workload that prenatal screening creates for the clinical laboratory, several automated random-access analyzers have been commercialized. The sensitivity and specificity of TORCH IgG and IgM assays on these systems vary, and manufacturers continue to reformulate assays to improve these characteristics. In our study, we evaluated the performance characteristics of seven TORCH assays (T. gondii, RV, and CMV IgG and IgM and HSV IgG) available on the Immulite 2000 immunoassay system (Siemens Healthcare Diagnostics Inc., Tarrytown, NY) and compared them to characteristics of the ETI-MAX 3000 TORCH assays (DiaSorin S. p. A., Saluggia, Vercelli, Italy), which are currently in use in our laboratory.This study was performed on sera (one sample/patient) prospectively collected consecutively from pregnant women referred to our microbiology laboratory for prenatal screening from September 2009 to March 2010. Approximately 500 total sera were tested for each analyte. Blood samples were clotted and centrifuged prior to testing. Results for sera analyzed using the Immulite 2000 system (IMM) were compared to TORCH assays on the ETI-MAX 3000 system (EMAX). IMM is an automated immunoassay analyzer with continuous random-access capabilities that uses enzyme-amplified chemiluminescence chemistry; EMAX is a fully automated enzyme immunoassay (EIA) microtiter plate analyzer with photometric measurement.IMM T. gondii IgG, RV IgG and IgM, CMV IgG, and HSV IgG assays are all 2-step, solid-phase, enzyme-enhanced immunoassays which have been described previously (4), whereas the T. gondii IgM and CMV IgM assays were recently reformulated and relicensed by Siemens. The T. gondii IgM assay employs a IgMcapture sandwich method, whereby patient IgM is captured by anti-IgM bound to the solid substrate. T. gondii IgM is then identified using a T. gondii IgM-specific antigen bound to the lightemitting agent alkaline phosphatase. The new Siemens T. gondii IgM assay uses P30 antigen as the capture antigen. This antigen has been shown to be well recognize...

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confidence: 82%

Performance Characteristics of Current-Generation Immulite 2000 TORCH Assays

Centonze

Tonolli

Fontana

2013

Clin Vaccine Immunol

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“…Yet, in our case, we observed that IgG titers varied by a factor 2 to 10 depending on the reagent assay, with the Elecsys assay showing the highest titers. Such a discrepancy between IgG titers expressed in international units (IU/ml) (43) for the same serum has been reported (44). This could, at least to some extent, be accounted for by the selected antigenic combinations (37,45,46) and the use of standards from different generations (World Health Organization [WHO]).…”

Section: Discussionmentioning

confidence: 95%

Help in the Choice of Automated or Semiautomated Immunoassays for Serological Diagnosis of Toxoplasmosis: Evaluation of Nine Immunoassays by the French National Reference Center for Toxoplasmosis

et al. 2016

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h Toxoplasmosis, a benign infection, is asymptomatic or paucisymptomatic in over 80% of cases, except in immunocompetent patients suffering from ocular toxoplasmosis or in immunocompromised patients with opportunistic or congenital toxoplasmosis. Diagnosis is based mainly on serology testing. Thus, we compared the performance of the nine most commonly used commercial automated or semiautomated immunoassays for IgG and IgM Toxoplasma gondii antibody detection, that is, the Advia Centaur, Architect, AxSYM, Elecsys, Enzygnost, Liaison, Platelia, VIDAS, and VIDIA assays. The assays were conducted on four panels of serum samples derived during routine testing from patients with an interfering disease and who exhibited a low IgG antibody level in one of two clinical settings, namely, acute or chronic toxoplasmosis. As a result, IgG sensitivities ranged from 97.1% to 100%, and IgG specificities ranged from 99.5% to 100%. For IgG quantification, strong differences in IgG titers (expressed in IU/ml) were noted depending on the assay used. IgM sensitivities ranged from 65% to 97.9%, and IgM specificities ranged from 92.6% to 100%. For defining the best serological strategies to be implemented, it appears crucial to compare the diagnostic performance of the different tests with respect to their specificity and sensitivity in detecting the presence of IgG and IgM antibodies.

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“…The measurement of IgG avidity was developed almost 20 years ago to exclude any infection acquired in the preceding 3 or 4 months using most commercial tests (16,17,18,19,20,21,22,23,24). Immunoblot analysis (Toxo II IgG test; LDBio, Lyon, France) may promptly confirm the seroconversion when IgG concentrations detected with routine tests are negative or equivocal (25,26,27). In fact, the appearance of IgM alone might be difficult to interpret because it can be due to nascent toxoplasmosis seroconversion or a nonspecific IgM reaction (28).…”

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confidence: 99%

Toxoplasma Seroconversion with Negative or Transient Immunoglobulin M in Pregnant Women: Myth or Reality? A French Multicenter Retrospective Study

et al. 2013

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Classically, Toxoplasma infection is associated with high levels of specific IgM antibody and a rise in specific IgG levels 1 to 3 weeks later. Atypical IgG seroconversion, without IgM detection or with transient IgM levels, has been described during serologic follow-up of seronegative pregnant women and raises difficulties in interpreting the results. To evaluate the frequency and the characteristics of these atypical cases of seroconversion, an investigation was conducted within the French National Reference Center for Toxoplasmosis, from which 26 cases collected from 12 laboratories belonging to the network were identified. The aim of this work was to retrospectively analyze the results of serologic testing, the treatments administered, and the results of prenatal and postnatal follow-up for these women. In each case, IgG antibodies were detected using both screening and confirmatory tests. IgM antibodies were not detected in 15 cases, and the levels were equivocal or low-positive in 11 cases. The IgG avidity results were low in 16 cases and high in one case. Most of the pregnant women (22/26) were treated with spiramycin from the time that IgG antibodies appeared until delivery. Amniotic fluid was analyzed for Toxoplasma gondii DNA by PCR in 11/26 cases, and the results were negative in all cases. Congenital toxoplasmosis was ruled out in 12/26 newborns. There was no abnormality observed at birth for 10 newborns and no information available for 4 newborns. In conclusion, when the interpretation of serological results is so difficult, it seems cautious to initiate treatment by spiramycin and to follow the pregnant women and their newborns.

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Bicentric Evaluation of Six Anti-Toxoplasma Immunoglobulin G (IgG) Automated Immunoassays and Comparison to the Toxo II IgG Western Blot

Cited by 32 publications

References 16 publications

Performance Characteristics of Current-Generation Immulite 2000 TORCH Assays

Performance Characteristics of Current-Generation Immulite 2000 TORCH Assays

Help in the Choice of Automated or Semiautomated Immunoassays for Serological Diagnosis of Toxoplasmosis: Evaluation of Nine Immunoassays by the French National Reference Center for Toxoplasmosis

Toxoplasma Seroconversion with Negative or Transient Immunoglobulin M in Pregnant Women: Myth or Reality? A French Multicenter Retrospective Study

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