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Screening and diagnosis of Rubella virus infection rely on testing for specific IgG and IgM. Immunoassays may yield different IgG results especially at low values, with difficulties in the evaluation of protective immunity. IgM levels decrease until negative a few weeks or months after acute infection, but individual and assay-related variability is common. To evaluate the performance characteristics of the automated immunoassay for Rubella IgG and IgM on the Abbott ARCHITECT. Twelve laboratories from 7 different Italian regions assayed 6268 routine specimens, comparing qualitative results for IgG and IgM and quantitative for IgG with other widespread immunoassays. Prevalence data for IgG were disaggregated by patients' group and by age in order to evaluate vaccination coverage. Qualitative concordance for IgG was 97.3% vs. Abbott AxSYM, 95.0% vs. DiaSorin Liaison and 97.7% vs. Behring Enzygnost; ARCHITECT was more sensitive than Liaison and equivalent to the other assays, with a good correlation of IU/mL values with AxSYM (r = 0.89). IgG prevalence was 87.1% among pregnant women, indicating a sub-optimal vaccine coverage. IgM reactivity was 1%, except in one site due to an outbreak. IgM concordance was 97.5% vs. Abbott AxSYM, 97.9% vs. DiaSorin Liaison and 97.7% vs. Behring Enzygnost; ARCHITECT was more specific than AxSYM. Our study confirms that in Italy Rubella vaccination coverage among pregnant women is insufficient. The new Rubella IgG and IgM assays on the ARCHITECT analyzer showed a good performance in comparison with other commercial methods. The results obtained and the good precision, indicate their suitability for routine testing.
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... Also, both assay reagents and instruments were from Abbott Laboratories and have similar principle as well as an excellent correlation. According to Portella's report, these two test modalities have an excellent qualitative concordance (97.3%) and only 0.3% truly discordant, as well very a high correlation coefficient value and almost linear relationship in 3,264 clinical samples 6 . Both assays also showed the same analytical range and cut-off value. ...
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Problem Vaccination is the best protection against rubella and congenital rubella infection. Although a high rate of immunization coverage is achieved in Taiwan, it is unknown if the vaccine induced immunity persists from the age of vaccination to childbearing age. Methods of study A total of 5,988 prenatal rubella IgG test results of young pregnant women aged 19‐23 years old from six hospitals during Jan. 2001 to Dec. 2008 and Jan. 2013 to Dec. 2017 were analyzed. We compared the rubella seropositivity rates and titers in these women who were vaccinated with MMR vaccine in four different vaccination age cohorts. Results The overall rubella seropositivity rate was 87.4% (95% CI: 86.6 – 88.3%) and the mean rubella IgG level was 39 IU/mL among young pregnant women aged 19‐23 years. Women in the elementary cohort had the highest rubella positivity of 90.8% (95% CI: 89.6 – 91.9%) and levels gradually decrease to 84.6% (95% CI: 82.4 – 86.7%) in 15‐month plus cohort. The average rubella IgG was only 25 IU/mL for the 15‐month plus cohort. Women in cohorts immunized at younger age exhibited significantly lower chances of being seropositive relative to women in older cohort after adjusting other factors (all p < 0.01). Conclusion The rubella seropositivity rate and rubella IgG levels were low among young women aged 19‐23 years, especially in cohorts immunized at younger age. Since rubella immunity wans over time, a third dose of MMR may be a protective strategy for women who conceive later in life.
... Detection of IgM is a very sensitive and rapid way to confirm a suspected rubella case, but its specificity is not absolute. Although the best commercial enzyme immunoassays (EIA) kits for rubella IgM have excellent performance, with a specificity of around 95 % [39][40][41][42], false positive results are always possible. In low prevalence or elimination settings, the positive predictive value of the rubella IgM assay drops virtually to zero. ...
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... It is important to note that neutralization assays were used to determine the initial antibody cut off recommendations, and that total IgG levels represent a surrogate marker for immunity. Furthermore, the measurement of total antibody levels can vary by manufacturer depending upon the selection of antigens and reference standards employed in the assay [11][12][13]. Studies on the development of the rubella vaccine showed long-lasting antibody responses were elicited [14], however waning levels of IgG populations [15,16]. ...
... All experiments were done in triplicate. The error bars represents standard deviations.with the previous reports363738, where the LOD and sensitivity of CLEIA were 2-8 fold better than that of ELISA, when passively adsorbed antibody was used in both the formats. However, they are contrary to other reports [39], where there was no difference in the sensitivity and specificity of CLEIA and ELISA. ...
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