Rubella Antibody, IgM
Label Mnemonic: RUBEIGM
Epic code: LAB4003
Downtime form: A-1a Doctor/Provider Orders - Pathology Core and Specialty Care Nursery
6240 RCP
Collection Medium:
Plasma Separator Tube 4.5 mL
Alternate Collection Media:
Call laboratory for additional acceptable specimen collection containers.
3.0 mL whole blood from light green top tube or TWO Microtainer® devices.
Testing Schedule:
24 hrs/day, 7 days a week, including holidays.
Turn Around Time:
3 hours (upon receipt in laboratory)
Reference Range:
Reference range and methodology changed effective 12/11/2012.

0.8 AI or less: Negative - No significant level of detectable rubella IgM antibody.

0.9-1.0 AI: Equivocal - Repeat testing in 10-14 days may be helpful.

1.1 AI or greater: Positive - IgM antibody to rubella detected, which may indicate a current or past rubella infection.
For workup related to possible rubella infection, acute and convalescent specimens must be labeled as such; parallel testing is preferred and convalescent specimens must be received within 30 days from receipt of the acute specimens. Please mark specimen plainly as "ACUTE" or "CONVALESCENT."

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.
Test Limitations:
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.
Multiplex Flow Immunoassay
CPT Code: