Evaluation of the Vitros ECiQ Immunodiagnostic System for Detection of Anti- Toxoplasma Immunoglobulin G and Immunoglobulin M Antibodies for Confirmatory Testing for Acute Toxoplasma gondii Infection in Pregnant Women

Abstract

Infection with Toxoplasma gondii is often asymptomatic and, when acquired during pregnancy, may lead to connatal toxoplasmosis in the offspring. The newly introduced Vitros anti-Toxoplasma immunoglobulin G (IgG) and IgM assays, designed for the Vitros ECiQ immunodiagnostic system, a fully automated system based on chemiluminescence, were evaluated as a screening method for the serological detection of acute and chronic Toxoplasma infections in the sera of 719 pregnant women. Infection with the protozoan Toxoplasma gondii is mostly asymptomatic for immunocompetent individuals (11). The incidence of gestational Toxoplasma infection in European countries ranges from 0.2 to 1.0% (7). Maternal infection during pregnancy may cause placental and fetal infections. Connatal toxoplasmosis is associated with a wide spectrum of clinical symptoms, such as retinochoroiditis, intracerebral calcifications, and hydrocephalus. These symptoms may be present at birth or may develop later in life, leading finally to blindness, psychomotor retardation, and hearing difficulties (13, 21).Austria and France are the only countries that have implemented nationwide obligatory serological screening programs for the detection of gestational Toxoplasma infections. These systems provide systematic serological assessment early in pregnancy and periodic follow-up of pregnant women at risk (7). Serological diagnosis of infection with T. gondii is performed indirectly by enzyme immunoassays, an indirect immunofluorescence test, and, more precisely, by the Sabin-Feldman dye test (18). The dye test is considered the reference test for the detection of Toxoplasma infection (16).Any serological test system has to meet several criteria of adequacy, such as high sensitivity and specificity, easy handling, and reproducible results under routine laboratory conditions. The present study investigated the newly introduced Vitros ECiQ Toxoplasma immunoglobulin G (IgG) and IgM assays (Ortho-Clinical Diagnostics, NJ) as a screening method for the diagnosis of acute and chronic Toxoplasma infections in the sera of pregnant women. The Vitros test results were compared with those of the Sabin-Feldman dye test and the immunosorbent agglutination assay (ISAGA) for the determination of anti-T. gondii-specific IgM (10). Diagnosis of maternal infection status was provided via routine serology by the toxoplasmosis reference laboratory at the Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria. In addition, the technical precision of both the Vitros Toxoplasma IgG and IgM assays was evaluated by serial specimen measurements. MATERIALS AND METHODSSamples and patients. Serum samples were collected from 719 healthy pregnant women according to the recommendations of the Austrian toxoplasmosis screening program and were submitted to the laboratory for routine analysis. The Sabin-Feldman dye test and the IgM ISAGA were performed within 24 to 48 h from the time when the samples were received. Sera were stored at Ϫ20°C. For the evaluat...

Prevalence and associated risk factors of Toxoplasma gondii in female farmworkers of southeastern Turkey

“…Based on our knowledge, control and serological screening programs should be implemented in the SAR in Turkey for the control of congenital T. gondii infections, as they have been implemented in Australia and France [30]. Reliable and faster diagnostic tests should be developed for both mother and fetus.…”

Parasitic infections and myositis

“…Serological tests for detection of IgG antibodies to T. gondii should be done using IFA (Silva et al 2002), ELISA (Kasper et al 2009), or IgG avidity test (Higa et al 2010). IgG appears within 1-2 weeks after infection and persists for the individual's lifetime (Montoya et al 2002).…”

Evaluation of Serological Prenatal Screening to Detect <b><i>Toxoplasma gondii</i></b> Infections in Austria

“…Thus, some women were overtested. Because commercial tests are not always able to differentiate between acute and chronic infection with a single serum sample [24,25], first serology should be done early in pregnancy to identify chronic infections and to determine if further testing is necessary.…”