Evaluation of the new ARCHITECT Rubella IgM assay

BackgroundRubella infections are usually characterized by mild self-limiting courses in immunocompetent individuals. However, infections in pregnant women during the first trimester of pregnancy pose a high risk of congenital rubella syndrome possibly resulting in severe defects in the unborn child. Rubella serology of a primary rubella infection is mainly determined by diagnostic confirmation of levels of specific IgM.Study designHere, we report on the performance of the Rubella IgM assay in development on the ARCHITECT instrument, a fully automated high throughput chemiluminescent microparticle immunoassay platform. Sensitivity was examined using commercially available seroconversion panels from vaccinated individuals; specificity was addressed by testing populations of pregnant women, blood donors and hospitalized patients. In addition, the potential for assay interference was evaluated by testing samples of several disease states. As methods of comparison AxSYM, BioMérieux VIDAS and Behring Rubella IgM assays were used.ResultsThe study demonstrates that the ARCHITECT Rubella IgM assay shows improved specificity compared to AxSYM and Behring. Seroconversion sensitivity is equivalent on all assays evaluated.ConclusionTogether with high throughput, optimized specificity and suppression of rheumatoid factor (RF) interference the ARCHITECT assay provides a useful improvement for the diagnosis of rubella serology.