Immunoblot evaluation of rubella humoral immunity in Portuguese women with negative or low-positive rubella IgG.

Despite its low incidence in Europe, rubella's immune status is still routinely assessed using commercial immunoassays. However, some discrepancies have been observed between these tests and the Immunoblot. The main objective of this study is to evaluate, by a commercial immunoblot, the immune status of a female population that had previously presented negative, low-positive, or equivocal rubella IgG with a commercial immunoassay. In total, 146 serum samples were reevaluated. The results demonstrated that 81 % and 73 % of the samples, were positive by Immunoblot (Immunoblot interpretation criterion 1 and criterion 2, respectively). Our results confirm previous studies, showing that Immunoblot can significantly reduce the false negatives for rubella in the female population. This application by avoiding unnecessary revaccinations represents a potential gain for health. However, it is pertinent to conduct an extended multidisciplinary discussion to analyse the pros and cons of this algorithm.