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Rubella IgM

Rubella Antibody, IgM, Rubella Antibody (IgM)

Test Codes

Testing requires pathology approval prior to collection.

Department

Send Outs

Instructions

This test is not included in the Beaumont Laboratory testing formulary, however, the Laboratory can facilitate specimen collection.

• This test requires pathology review and pre-authorization by the Michigan Department of Human Health Services. Contact the Send Outs Laboratory at 248-551-9045 before ordering this test.
• Specimens received without prior approval will not be shipped.
• Once approved, order test as a Miscellaneous Send Out (XMISC).

Specimen Collection Criteria

Collect (preferred specimen): Two plain Red-top tubes.
Also acceptable: Two Gold-top SST tubes.

Physician Office/Draw Specimen Preparation

Let specimen clot 30-60 minutes then immediately centrifuge to separate serum from cells. Transfer serum to a plastic transport tube and refrigerate (2-8°C or 36-46°F).

Preparation for Courier Transport

Transport: 3.0 mL serum, refrigerated (2-8 °C or 36-46 °F). (Minimum: 1.0 mL)

Rejection Criteria

Specimens received without prior pathology review and approval.

Specimen not collected and processed as indicated.

In-Lab Processing

Let specimen clot 30-60 minutes then immediately centrifuge to separate serum from cells. Transfer serum to a plastic transport tube and refrigerate (2-8°C or 36-46°F).

Transport: 3.0 mL serum, refrigerated (2-8 °C or 36-46 °F). (Minimum: 1.0 mL)

Storage

Specimen Stability for Testing:

Room Temperature (20-26°C or 68-78.8°F): 24 hours
Refrigerated (2-8°C or 36-46°F): 7 days
Frozen (-20°C/-4°F or below): 30 days

Specimen Storage in Department Prior to Disposal:

Specimen retention time is determined by the policy of the reference laboratory. Contact the Send Outs Laboratory with any questions.

Laboratory

Sent to Michigan Department of Human Health Services (MDHHS) Lansing, MI.

Performed

Varies, weekly.
Results available in 7-14 days.

Reference Range

Absent.

Test Methodology

IgM Capture Enzyme Immunoassay (EIA).

Interpretation

• False negative results may occur if the specimen is collected very early during the acute stage or late after the convalescent stage of infection. Negative results by this test do not preclude recent primary rubella infection.
• Epstein-Barr Virus (EBV) infections have been suspected to elicit antigen-specific IgM responses in individuals previously sensitized to a variety of non-EBV infectious agents. False-positive results may be caused by IgM type rheumatoid factor.

Clinical Utility

• Rubella IgM testing is used for the qualitative measurement of IgM antibodies to rubella virus in human serum and as an aid in the diagnosis of primary or acute infection.
• Rubella IgM is first detectable 1-5 days after the rash appears. Peak titers are observed 1-4 weeks after infection and IgM antibody titers often drop to undetectable levels after 6-12 weeks. (1)

Clinical Disease

• Children and adults with rubella infections present with a mild self-limiting disease characterized by rash, fever, and lymphadenopathy. The rash initially appears on the face and rapidly spreads to the trunk, arms, and legs, and disappears in 1-3 days. Adults frequently develop transient polyarthralgia and arthritis after natural infection. Other complications such as thrombocytopenia and encephalopathy rarely occur.
• Rubella infections during pregnancy can frequently cause fetal death, premature delivery, and an array of congenital defects. The effects on the fetus depend upon the time of infection. Generally, the younger the fetus, the more severe the resulting disease. During the first 8 weeks of gestation, the fetus has a 40-60% chance of spontaneous abortion or of acquiring multiple congenital defects. At 12 weeks, the fetus has a 30-35% chance of developing a single defect such as deafness or congenital heart disease. Fetal infection during the 16th week carries a 10% risk of a single congenital defect. Occasionally, fetal damage (deafness) has been observed when rubella infections occur as late as the 20th week of gestation. Infants with congenital rubella may excrete high concentrations of virus in nasopharyngeal and other secretions until they are nearly 2 years of age. Contact with these children possesses a risk for susceptible pregnant women. (1)

Epidemiology

Most rubella cases occur in the spring and early summer (February-May). Prior to 1965, rubella epidemics occurred every 6-9 years and major epidemics occurred at 30 year intervals. The incidence of epidemic rubella has been drastically reduced by immunization programs. (1)

Incubation Period

The incubation period is 16-21 days with a mean of 18 days. Patients are infectious for 1 week before and 7-10 days after the rash appears. (1)

Transmission

Rubella is mildly contagious. The disease is transmitted through inhalation of virus-laden aerosol droplets. (1)

Reference

1. Wiedbrauk D, Johnston SLG. Manual of Clinical Virology, Raven Press, New York, NY, 1993.

CPT Codes

N/A.

Contacts

Last Updated

9/17/2023