Comparison of two commercial immunoassays for the detection of anti-rubella IgM and IgG in pediatric patients.

The only threatening modality of rubella is the Congenital Rubella Syndrome that affects fetuses of women who acquire infection during early pregnancy. Laboratory diagnosis is based on serological parameters. We compared anti-rubella IgM and IgG detection of two commercial immunoassay kits (Abbott and Roche). Although we observed an agreement of 97.8% for IgM and 95.7% for IgG when the categories positive, negative and indeterminate were considered, mean titers of IgG and the absorbance/cut off of IgM were statistically different for both kits, thus corroborating the idea that serological results depend very much on the methodology and must be carefully interpreted.