The fully automated IMx immunoassay analyzer was used to develop a system for the detection of
IgG and
IgM antibodies to rubella virus for immune status screening and diagnosis of primary
infections.
Reagents and assay protocol software were developed using rubella virus sensitized microparticles as the solid phase to capture specific
antibodies from serum samples. Anti-human
IgG or
IgM antibody coupled to
alkaline phosphatase enzyme followed by methylumbelliferyl
phosphate substrate was used to detect the presence or absence of
antibodies specific to the
antigens on the solid phase. To evaluate the efficacy of the IMx
rubella IgG assay, immune status screening was performed with a clinical patient population of 501 sera. When compared to an
IgG specific
enzyme immunoassay and passive hemagglutination assay the agreement was greater than 99%. The IMx
rubella IgM assay was utilized to determine the presence of
rubella specific
IgM antibodies in 462 sera. These results were compared to
IgM specific
enzyme immunoassay results and also demonstrated greater than 99% agreement. Seroconversion following
rubella vaccination of susceptible individuals was demonstrated by
IgG and
IgM antibody responses as early as two weeks postvaccination. In addition to automation, the IMx system offers rapid assay times and calibration curve storage without sacrificing clinical efficacy.