Rubella Antibody (IgM)

For Specimen Integrity during Extreme Weather see the “Lockbox Usage in Extreme Weather” document at the top of this page.

Test Code

CPT Codes

Preferred Specimen
1 mL serum

Minimum Volume
0.6 mL

Transport Temperature
Room temperature

Specimen Stability
Room temperature: 4 days
Refrigerated: 7 days
Frozen: 30 days

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Gross hemolysis • Grossly lipemic

Immunoassay (IA)

Setup Schedule
Set up: Tues-Sat; Report available: 1-3 days

Reference Range
AU/mL Interpretation
<20.00 Negative
20.00-24.99 Equivocal
≥25.00 Positive

Clinical Significance
Rubella is an acute exanthematous viral infection of children and adults. Rash, fever and lymphadenopathy characterize the illness. While many infections are subclinical, this virus has the potential to cause fetal infection with resultant birth defects. In the absence of a current or recent infection, a demonstration of specific IgG on a serum sample is evidence of immunity to rubella. A positive rubella IgM result does not necessarily indicate current or recent infection. Without a history of exposure to rubella or symptoms consistent with rubella, the IgM result may be difficult to interpret. Rubella IgM can be false positive due to other causes (e.g., parvovirus, rheumatoid factor, cytomegalovirus). Rubella IgM may also persist for more than 12 months after vaccination or natural infection. For a serologic diagnosis of congenital rubella in the neonatal period, antibody to rubella virus should be measured in both infant and maternal sera. If IgM is detected in a newborn infants serum, it is probable that transplacental rubella infection has occurred.

Performing Laboratory
Quest Diagnostics Nichols Institute
14225 Newbrook Drive
Chantilly, VA 20153

Last Updated: December 6, 2021

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.