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Test ID: Rubella Antibody IgM
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Rubella Antibody IgM
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Detection of Rubella IgM Antibody in Blood
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Useful For
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Determination of the immune status of an individual and to aid in the presumptive diagnosis of an acute or recent rubella infection in individuals, including women of childbearing age.
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Method name and description
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Electrochemiluminescence immunoassay (ECLIA): µ‑Capture test principle.
Measurement of antigen or antibody based on the change in electrochemiluminescence (ECL) signal before and after immunoreaction. Results are determined automatically by the software by comparing the electrochemiluminescence signal obtained from the reaction product of the sample with the signal of the cutoff value previously obtained by calibration.
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Clinical information
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Rubella virus is the etiological agent of German measles, a commonly mild rash disease which occurs usually during childhood. However, Rubella can be a serious disease when a pregnant woman becomes infected especially during the first trimester of pregnancy.
Rubella virus can be transmitted through the placenta and results in fetal death or causes severe malformations to the fetus, commonly summarized as congenital Rubella syndrome (CRS). In congenital rubella, antibody is detectable in infants up to one year of age.
Today, infant vaccination programs and the vaccination of women in childbearing age who are susceptible to Rubella infection have considerably reduced the incidence of acute Rubella infection. The presence of IgG antibodies to Rubella virus indicates a previous exposure either by vaccination or prior Rubella infection and is indicative of immunity.
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Specimen type / Specimen volume / Specimen container
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Specimen type: Serum, Plasma
Minimum volume of sample: 1 mL
Serum: Plain tube (red or yellow top)
Plasma: Li‑heparin tube
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Collection instructions / Special Precautions / Timing of collection
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Collect blood by standard venipuncture techniques as per specimen requirements. When processing samples in primary tubes (sample collection systems), follow the instructions of the tube manufacturer.
Specimens should not be altered subsequently with additives (biocides, antioxidants or substances possibly changing the pH of the sample) in order to avoid erroneous findings.
Pooled samples and other artificial material may have different effects on different assays and thus may lead to discrepant findings
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Storage and transport instructions
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Storage: 2 days at 20 – 25°C
3 weeks at 2 – 8°C;
3 months at ‑20 °C (± 5 °C)
Transport: 2-25°C
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Specimen Rejection Criteria
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Grossly hemolyzed, icteric and lipemic samples, wrong collection container, insufficient sample and heat‑inactivated samples.
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Biological reference intervals and clinical decision values
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Analyte/Unit
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Result message
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Result message
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Interpretation/ further steps
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COI*
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< 0.8 COI
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Non-reactive
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Non-reactive in the Elecsys Rubella IgM assay
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COI
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≥ 0.8 - < 1.0 COI
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Indeterminate
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The sample should be retested. In case the result is still indeterminate, a second sample should be tested e.g. within 1 week. A significant increase of the Rubella IgG antibody titer from a first to a second sample supports the diagnosis of acute Rubella infection.
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COI
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≥ 1.0 COI
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Reactive
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Reactive in the Elecsys Rubella IgM assay.
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*COI = cutoff index
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Factors affecting test performance and result interpretation
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Increasing amounts of unspecific human IgM may lead to a decrease in the recovery of positive samples with the Elecsys Rubella IgM assay
In rare cases, interference due to extremely high titers of antibodies to analyte‑specific antibodies, streptavidin or ruthenium can occur. These effects are minimized by suitable test design
The detection of rubella-specific IgM antibodies indicates recent or current infection. In congenital rubella, antibody is detectable in infants up to one year of age. Follow up testing of IgM is advisable after 6-8 wks of rash onset.
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Turnaround time / Days and times test performed / Specimen retention time
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Daily (24/7)
Turn-around time:
Routine: One working day
Specimen Retention: 4 days
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