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Test ID: Rubella IgG Avidity
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Rubella IgG Avidity Antibody
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The test is lab order only
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Useful For
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Avidity determination of IgG class antibodies against Rubella virus in human serum or plasma of pregnant women.
This test will be added by the laboratory as a reflex test for pregnant women if the rubella IgM/IgG antibody result is positive.
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Method name and description
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Enzyme-linked Immunosorbent Assay (ELISA)
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Aliases
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Antibody avidity - Rubella
IgG avidity index - Rubella
Rubella virus - antibody avidity
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Specimen type / Specimen volume / Specimen container
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Specimen type: Serum
Specimen volume: 3-5 mL
Specimen container: Serum collected in Yellow top gel tube
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Collection instructions / Special Precautions / Timing of collection
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Collection by venipuncture as per organization guidelines
No special precautions / no timing of collection
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Storage and transport instructions
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Maintain specimen at 2-8°C
The specimens should be transported to Virology Section in cold box immediately
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Specimen Rejection Criteria
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Quantity of blood not sufficient
Wrong blood container
Container breakage / sample leaking
Lipemic sample
Grossly hemolyzed serum
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Biological reference intervals and clinical decision values
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- High rubella IgG avidity: Indication of high-avidity antibodies, suggest that recent primary infection is unlikely
- Low rubella IgG avidity: Indication of low-avidity antibodies, suggestive of recent infection
- Grayzone: neither confirms nor excludes antibody detection and should be reviewed in the light of clinical findings. It is recommended to collect a second sample not less than 7 days later and to test it together with the first sample.
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Factors affecting test performance and result interpretation
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- High IgG antibody titers in acute infection may produce false high IgG avidity results due to predominance of high-avidity antibodies.
- It must be taken into consideration that anti-rubella IgM antibodies may be present months after an infection.
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Turnaround time / Days and times test performed / Specimen retention time
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Turnaround time: Within 7 calendar days
Days and times test performed: Twice a week.
Specimen retention time: 2 weeks
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