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Evaluation of an automated chemiluminescent immunoassay for the detection of anti-rubella virus IgM antibodies

Abstract number: 1733_665

Pustowoit B., Liebert U.G.

Background and Objectives: Rubella, commonly known as German measles, occurs worldwide. In an acute rubella infection acquired either naturally or via vaccination, IgM antibodies appear in the patient serum at the onset of clinical illness and persist for a period of 4 to 5 weeks. However, low IgM levels may not necessarily indicate a recent rubella infection. A fully automated assay for the qualitative detection of anti-Rubella IgM in human serum developed on the Access® immunoassay systems (Beckman Coulter Inc.) was studied including clinical specificity and sensitivity as well as performance with potential cross reactivity panels. A study was performed with a panel named ``long persistent Rubella IgM'' referring to positive results obtained with other anti-Rubella IgM method but not considered as acute infection or recent vaccination.

Methods: The specificity was studied with a population of 96 samples considered negative in IgM (>360 days after exanthema or vaccination). Sensitivity was studied with 31 samples from a Rubella outbreak and 12 samples from recently vaccinated people. The evaluation of potential cross reactivity was based on 30 samples from individuals who had serological evidence of acute infections with Mumps (n = 9), EBV (n = 5), CMV (n = 3), Influenza A (n = 4) and other pathogenic microorganisms (n = 10). ``Long persistent IgM'' were studied with samples from persons with positive IgM with an other method but with high level of IgG avidity and/or presence of E2 band in native immunoblot (inconsistent with acute Rubella). Discrepant results were confirmed using additional EIA tests, avidity of anti-Rubella IgG as well as native immunoblot test for determination of IgG antibodies against Rubella virus proteins.

Results: In this study, Access®Rubella IgM exhibited a specificity of 98.09% and a sensitivity of 97.61%. A sensitivity of 100% was noted with seroconversion panels. Two samples (one positive in anti-E. coli and one positive in Influenza A IgA) presented a cross-reaction. Referring to the ``long persistent'' rubella IgM panel, 8 samples were negative with Access Rubella IgM in accordance with the sample status (no acute infection or recent vaccination).

Conclusion: The Access® anti-Rubella IgM assay combines clinical performance, with good sensitivity, specificity with the advantage of a rapid, automated, random access immunoassay system.

Session Details

Date: 31/03/2007
Time: 00:00-00:00
Session name: European Society of Clinical Microbiology and Infectious Diseases
Subject:
Location: ICC, Munich, Germany
Presentation type:
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