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.

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. The combination of the Vitros IgG and IgM assays demonstrated a sensitivity and a specificity of 100% for the successful detection of all acute T. gondii infections by comparison with the Sabin-Feldman dye test as the reference test. The Vitros IgG assay parameter revealed a sensitivity of 95.0%, a specificity of 100.0%, a positive predictive value of 100.0%, a negative predictive value of 86.2%, and an overall agreement of 96.2% by comparison with the dye test. Comparison of the Vitros Toxoplasma IgM assay with the immunosorbent agglutination assay yielded values of 77.1%, 99.0%, 97.7%, 88.5%, and 91.1%, respectively. Subsequent receiver operating characteristic curve analysis for the accurate detection of Toxoplasma IgM in acute (n = 90) and chronic (n = 461) infections demonstrated high sensitivity (92.2%) and specificity (81.6%). The combination of a Toxoplasma-specific IgG assay with specific IgM antibody detection has improved the diagnosis of T. gondii infection by decreasing follow-up testing. Nonetheless, positive Toxoplasma IgM test results during pregnancy necessitate confirmatory testing by a reference laboratory to ensure fast and, above all, accurate test results.

Caffeine monitoring in infants: comparison of automated (VITROS 5, 1 FS) chemistry system versus HPLC analysis.

This is the first study comparing the caffeine testing by HPLC to the MicroTip Technology patented by Ortho-Clinical Diagnostics. For the determination of the precision for intra-run and day to day variances, control materials with concentration ranges between 2.3 microg/mL and 23.3 microg/mL were used. Test evaluation was done using plasma samples. The coefficient of variation for intra-run precision was calculated to range from 4.3% to 2.1%. The coefficients of variation for the day-to-day precision were between 4.9% and 2.3%. A coefficient of correlation of 0.99% was calculated for the comparison of the two methods. In the statistical analysis of the comparison of the methods. Differences between + 4.5% and - 0.92% could be found. The HPLC system must be ready for use at any time necessitating maintenance and increased costs. This, in addition to the low sample throughput for caffeine analysis and the findings of this study favour the use of an automated clinical chemistry system.

Evaluation of the VITROS 5,1 FS chemistry system in a large pediatric laboratory.

The VITROS 5,1 FS analytical system was evaluated. The measurement of the serum proteins and HDL cholesterol with the newly developed MicroTip technology was compared with other nephelometric and turbidimetric methods. The within-run imprecision for apolipoprotein A1, apolipoprotein B, complement 3, complement 4, transferrin, immunoglobulin A, immunoglobulin M, immunoglobulin G and HDL cholesterol showed coefficients of variation between 0.4% and 4.7%. The day-to-day imprecision showed coefficients of variation between 0.5% and 4.0%. The correlation with the comparative methods (nephelometric or turbidimetric) was good, with Pearson correlation coefficients of between 0.959 and 0.995. The comparison of apolipoprotein Al showed a slope of about 0.76. An explanation for the difference could not be found. The VITROS 5,1 FS analytical system is a reliable routine instrument which fits into a large pediatric laboratory of a university.