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Elecsys® Rubella IgM

Immunoassay for the qualitative determination of IgM-antibodies against rubella virus

Elecsys® Rubella IgM

Immunoassay for the qualitative determination of IgM-antibodies against rubella virus

Rubella virus causes German measles, a mild rash disease which commonly occurs during childhood. It is highly contagious and mainly transmitted by the respiratory route.1 Rubella can also occur vertically from an infected mother to her child.1 Postnatal infection is rarely associated with complications, however, primary infection mainly during early pregnancy is a serious condition, as it may cause miscarriages or congenital rubella syndrome (CRS). CRS includes blindness, deafness, congenital heart disease and mental retardation1.

Today’s vaccination programs have considerably reduced the incidence of acute rubella and CRS2. Since rubella may present atypically or with non-specific symptoms and signs that may be caused by other viruses which do not have a teratogenic potential, it is important that the clinical diagnosis be confirmed by laboratory tests, particularly during pregnancy.3

The presence of IgM antibodies to rubella virus usually indicates an acute infection, but may also be unspecific or persistent4. After natural infection IgM antibodies may last for 1 – 3 months, while vaccination induced IgM antibodies stay longer (years) at low levels5. Seroconversion of specific rubella antibodies or a significant rise of the Rubella IgG antibody titer from a first to a second sample may further support the diagnosis of acute Rubella infection.

Elecsys® Rubella IgM

Elecsys® Rubella IgM6

  • Systems

    cobas e 411 analyzer, cobas e 601 / cobas e 602 modules, cobas e 402 / cobas e 801 analytical units

  • Testing Time

    18 minutes

  • Test principle

    μ-capture assay

  • Calibration

    2-point

  • Interpretation

    COI <0.8 = non-reactive
    COI ≥0.8 – <1.0 = borderline
    COI ≥1.0 = reactive

  • Traceability

    This method has been standardized against a Roche standard (arbitrary units)

  • Sample material

    Serum collected using standard sampling tubes or tubes containing separating gel. Li-heparin, Na-heparin, K2-EDTA, K3-EDTA and Na-citrate plasma. Plasma tubes containing separating gel can be used.

  • Sample volume

    10 μL cobas e 411 analyzer, cobas e 601 / cobas e 602 modules
    6 μL cobas e 402 / cobas e 801 analytical units

  • Onboard stability

    14 days for cobas e 411 analyzer, cobas e 601 / cobas e 602 modules
    16 weeks for cobas e 402 / cobas e 801 analytical units

  • Intermediate precision

    cobas e 411 analyzer: CV 1.9 – 4.1 %   
    cobas e 601 / 602 modules: CV 2.7 %    
    cobas e 402 / cobas e 801 analytical units: CV 1.5 – 1.7 %

  • Sensitivity in early acute infection (< 30 days)

    80 % (n = 84)
    96 % (n = 25) 

  • Relative specificity

    98.7 % (n = 554) lower 95 % C.I.: 97.6 %
    99.0 % (n = 993) lower 95 % C.I.: 98.3 %    

References

  1. Best JM. Rubella.Seminars in Fetal & Neonatal Medicine. 2007; 12:182e192.
  2. The Measles & Rubella initiative. 2020 Annual Summary.  [Internet; updated 2022 Aug; cited 2022 Oct 24]. Available from: https://s3.amazonaws.com/wp-agility2/measles/wp-content/uploads/2022/08/MRI-2020-Annual-Summary.pdf.
  3. Best JM, Enders G. Rubella Viruses. Laboratory Diagnosis of Rubella and Congenital Rubella - Chapter 3. Elsevier B.V. 2007;39-77.
  4. Best JM, et al. Interpretation of rubella serology in pregnancy—pitfalls and problems. BMJ 2002;325:147
  5. Vauloup-Fellous C, Grangeot-Keros L. Humoral Immune Response after Primary Rubella Virus Infection and after Vaccination. Clinical and Vaccine Immunology. 2007;14 (5):644–647.
  6. Elecsys® Rubella IgM (#04618831190, #07027796190) method sheet 2022, V. 13.0 and V.4.0.