ARUP's Laboratory Test Directory

Rubella Antibodies, IgG and IgM : 0050552

Mnemonic: RUBE G/M

Methodology: Chemiluminescent Immunoassay
Performed: Sun-Sat
Reported: Within 24 hours
Specimen Required: Collect: Serum separator tube.

Specimen Preparation: Allow specimen to clot completely at room temperature. Separate serum from cells ASAP or within 2 hours of collection. Transfer 2 mL serum to an ARUP Standard Transport Tube. (Min: 0.5 mL) Parallel testing is preferred and convalescent specimens must be received within 30 days from receipt of the acute specimens. Mark specimens plainly as "acute" or "convalescent."

Storage/Transport Temperature: Refrigerated.

Unacceptable Conditions: Urine. Contaminated, heat-inactivated, or hemolyzed specimens.

Stability (collection to initiation of testing): After separation from cells: Ambient: 48 hours; Refrigerated: 2 weeks; Frozen: 1 year (avoid repeated freeze/thaw cycles)
Reference Interval:
 
Test Number Components Reference Interval
0050771Rubella Antibody, IgG  
 
Less than 9 IU/mL: Not Detected.
9-9.9 IU/mL: Indeterminate - Repeat testing in 10-14 days may be helpful.
10 IU/mL or greater: Detected.
0050551Rubella Antibody, IgM  
 
19.9 AU/mL or less: Not Detected.
20.0 - 24.9 AU/mL: Indeterminate - Repeat testing in 10-14 days may be helpful.
25.0 AU/mL or greater: Detected - IgM antibody to rubella detected, which may indicate a current or recent infection or immunization.

Interpretive Data: Testing immediately post-exposure is of no value without a later convalescent specimen. While the presence of IgM antibodies suggests current or recent infection, low levels of IgM antibodies may occasionally persist for more than 12 months post-infection or immunization.

The best evidence for current infection is a significant change on two appropriately timed specimens, where both tests are done in the same laboratory at the same time.
CPT Code(s): 86317; 86762