In 2005, the Centers for Disease Control and Prevention (CDC) announced the absence of endemic transmission of rubella in the United States, largely due to successful vaccination programs. Fewer than 10 cases of rubella were reported in 2004, and the majority of these cases occurred in individuals born outside the United States. The incidence of congenital rubella syndrome (CRS) has also been significantly reduced, with a total of 4 cases of CRS being reported to the CDC during 2001-2004. Given the low prevalence of rubella in the United States, routine serologic testing for IgM-class antibodies to this virus may yield false positive results, which can negatively impact patient care. This is especially problematic when rubella IgM testing is included in the routine screening of asymptomatic, pregnant women. Rubella Virus Antibody, IgG, is available for the determination of immune status to rubella.