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Test ID RBPG Rubella Antibodies, IgG, Serum

Reporting Name

Rubella Ab, IgG, S

Useful For

Determination of immune status to the rubella virus

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

Serum


Specimen Required


Container/Tube: 

Preferred: Serum gel

Acceptable: Red top

Specimen Volume: 0.5 mL


Specimen Minimum Volume

0.4 mL

Specimen Stability Information

Specimen Type Temperature Time
Serum Refrigerated (preferred) 14 days
  Frozen  14 days

Reference Values

Vaccinated: positive (≥1.0 AI)

Unvaccinated: negative (≤0.7 AI)

Reference values apply to all ages.

Day(s) and Time(s) Performed

Monday through Saturday, 9 a.m.

Test Classification

This test has been cleared or approved by the U.S. Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

CPT Code Information

86762

LOINC Code Information

Test ID Test Order Name Order LOINC Value
RBPG Rubella Ab, IgG, S 5334-8

 

Result ID Test Result Name Result LOINC Value
RBG Rubella Ab, IgG, S 40667-8
DEXG2 Rubella IgG Antibody Index 52986-7

Clinical Information

Rubella (German or 3-day measles) is a member of the Togavirus family and humans remain the only natural host for this virus. Transmission is typically through inhalation of infectious aerosolized respiratory droplets and the incubation period following exposure can range from 12 to 23 days.(1) Infection is generally mild and self-limited, and is characterized by a maculopapular rash beginning on the face and spreading to the trunk and extremities, fever, malaise, and lymphadenopathy.(2)

 

Primary in utero rubella infections can lead to severe sequelae for the fetus, particularly if infection occurs within the first 4 months of gestation. Congenital rubella syndrome is often associated with hearing loss, cardiovascular and ocular defects.(3)

 

The United States 2-dose measles, mumps, rubella (MMR) vaccination program, which calls for vaccination of all children, leads to seroconversion in 95% of children following the first dose.(1) A total of 4 cases of rubella were reported to the CDC in 2011 without any cases of congenital rubella syndrome.(4) Due to the success of the national vaccination program, rubella is no longer considered endemic in the United States (www.cdc.gov/rubella). However, immunity may wane with age as approximately 80% to 90% of adults will show serologic evidence of immunity to rubella.

Interpretation

Positive: Antibody index (AI) value of 1.0 or higher

-The reported AI value is for reference only. This is a qualitative test and the numeric value of the AI is not indicative of the amount of antibody present. AI values above the manufacturer recommended cutoff for this assay indicate that specific antibodies were detected, suggesting prior exposure or vaccination.

-The presence of detectable IgG-class antibodies indicates immunity to the rubella virus through prior immunization or exposure. Individuals testing positive are considered immune to rubella infection.

 

Equivocal: AI value 0.8-0.9

Submit an additional sample for testing in 10 to 14 days to demonstrate IgG seroconversion if recently vaccinated or if otherwise clinically indicated.

 

Negative: AI value of 0.7 or lower

The absence of detectable IgG-class antibodies suggests the lack of a specific immune response to immunization or no prior exposure to the rubella virus.

Cautions

IgG-class antibodies to rubella virus may be present in serum specimens from individuals who have received blood products within the past several months, but who have not been immunized or experienced past infection with this virus.

 

Serum samples drawn early during acute phase of infection may be negative for IgG-class antibodies to this virus.

 

The presence of anti-rubella-IgG antibodies does not exclude the possibility of a recent or ongoing infection. Testing for IgM-class antibodies to rubella should be performed at a state health laboratory or at the CDC if the clinical presentation is suggestive of acute rubella infection.

Clinical Reference

1. American Academy of Pediatrics. Rubella. In Red Book. 2012 Report of the Committee on Infectious Diseases. Edited by LK Pickering, Elk Grove Village, IL, 2012

2. Best JM: Rubella. Semin Fetal Neonatal Med 2007;12(3):182

3. Duszak RS: Congenital rubella syndrome-major review. Optometry 2009;80(1):36

4. Morbidity and Mortality Weekly Report: Notifiable Diseases and Mortality Tables 2012;61(34):466-479

Analytic Time

Same day/1 day

Reject Due To

Hemolysis

Mild OK; Gross reject

Lipemia

Mild OK; Gross reject

Icterus

Mild OK; Gross reject

Other

Heat-inactivated specimen

NY State Approved

Yes

Method Name

Multiplex Flow Immunoassay (MFI)

Forms

If not ordering electronically, complete, print, and send a Microbiology Test Request (T244) with the specimen.