Adult Preferred Mimimum: 2.0 mL serum Absolute Minimum: 0.5 mL serum

Rubella Antibody, IgG Less than 5 IU/mL: Negative No significant level of detectable rubella IgG antibody. 5-9 IU/mL: Equivocal Repeat testing in 10-14 days may be helpful. Greater than 10 IU/mL: Positive IgG antibody to rubella detected, which may indicate a current or previous exposure/immunization to rubella. Rubella Antibody, IgM 0.89 IV of less: Negative No significant level of detectable rubella IgM antibody. 0.90-1.09 IV: Equivocal Repeat testing in 10-14 days may be helpful. 1.10 IV or greater: Positive IgM antibody to rubella detected, which may indicate a current or recent infection or immunization.

In children and adults, rubella infection usually results in a mild exanthematous disease. However, infection during pregnancy, particularly in the first trimester, can result in fetal death or the "rubella syndrome," a spectrum of congenital defects that includes cataracts, deafness, glaucoma, congenital heart disease, and mental retardation. About ten to 20 percent of newborns infected in utero fail to survive past the first year of life. Since complications of congenital rubella infection are so severe, diagnosis of infection during the first trimester of pregnancy may influence the decision to terminate or continue the pregnancy. Thus, it is important to determine the rubella immune status in women of child-bearing age, in pregnant women, and in individuals who may have close contact with them, such as hospital personnel and preschool children. In a patient suffering from a primary rubella infection, the appearance of both IgG and IgM antibodies is associated with the appearance of clinical signs and symptoms when present. IgM antibodies become detectable in a few days after the onset of signs and symptoms and reach peak levels in seven to ten days. These antibodies persist, but rapidly diminish in concentration over the next four to five weeks until the antibody is no longer clinically detectable. The presence of IgM antibody in a single specimen suggests that the patient has recently experienced a rubella infection. In most cases, the infection probably occurred within the preceding one to three months. Rubella IgM antibody in a newborn's serum suggests congenital infection since IgM from the mother is not transferred to the infant across the placenta. The infected infant, in contrast to a woman with prenatal rubella, may continue to produce rubella-specific IgM for several months.