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 titre from a first to a second sample may further support the diagnosis of acute Rubella infection.

Elecsys® Rubella IgM

Elecsys® Rubella IgM

  • Systems

    cobas e 411 analyser, cobas e 601 / cobas e 602 modules, cobas e 801 module

  • Testing Time

    18 minutes

  • Test principle

    μ-capture assay

  • Calibration

    2-point

  • Interpretation

    COI <0.8 = non-reactive
    COI ≥0.8 – <1.0 = gray zone
    COI ≥1.0 = reactive

  • Traceability

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

  • Sample material

    cobas e 411 analyser, cobas e 601 / cobas e 602 modules: Serum collected using standard sampling tubes or tubes containing separating gel. Li‑heparin, K3‑EDTA and Na-citrate plasma. Do not use plasma treated with sodium fluoride and potassium oxalate.

     

    cobas e 801 module: 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 analyser, cobas e 601 / cobas e 602 modules
    6 μL cobas e 801 module

  • Onboard stability

    14 days for cobas e 411 analyser, cobas e 601 / cobas e 602 modules
    16 weeks for cobas e 801 module

  • Intermediate precision

    cobas e 411 analyser: CV 1.9 – 4.1 %   
    cobas e 601 / 602 modules: CV 2.7 – 3.4 %    
    cobas e 801 module: CV 1.5 – 4.2 %

  • 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, J.M. (2007). Seminars in Fetal & Neonatal Medicine 12, 182e192.
  2. http://measlesrubellainitiative.org/wp-content/uploads/2017/01/MRI-2014-Annual-Report_FINAL.pdf
  3. Best, J.M. et al. (2007). In: Rubella Viruses [Internet]. Elsevier B.V., 39-77.
  4. Best, J.M. at al. (2002). BMJ 325, 147-148.
  5. Vauloup-Fellous, C. et al. (2007) Clin Vaccine Immunol. 14, 5, 644-7.