Rubella virus is the etiological agent of German measles, a commonly mild rash disease which occurs usually during childhood. It is spread by small droplets via the respiratory route. Postnatal acquired infection is seldom associated with complications.
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 can result in fetal death or may cause severe malforations to the fetus, commonly summarized as congenital Rubella syndrome (CRS). CRS is an important cause of blindness, deafness, congenital heart disease and mental retardation. Today infant vaccination programs and the vaccination of women in child-bearing age who are susceptible to Rubella infection have considerably reduced the incidence of acute Rubella infection and the incidence of CRS.
The detection of Rubella-specific antibodies is used to determine the immune status of an individual and to aid in the diagnosis of acute Rubella infection. The presence of IgG antibodies to Rubella virus indicates a previous exposure either by vaccinaiton or prior Rubella infection and is indicative of presumptive immunity.
The detection of Rubella-specific IgM antibodies is used as an aid in the diagnosis of acute Rubella infection. Seroconversion of specific Rubella antibodies or a significant rise of the IgG antibody titer from a first to a second sample may support the diagnosis of acute Rubella infection. Recombinant
Rubella-like particles (RLP) have proven to replace authentic Rubella virus as an antigen in diagnostic assays. A recombinant part of the E1 (envelope1) protein of Rubella virus is used to supplement the Elecsys assay.
Useful For
This assay is for the in vitro quantitative determination of IgG antibodies to rubella virus in human serum and Li-heparin plasma.
This assay may be used as an aid in the assessment of immune status to rubella in individuals including women of childbearing age.
Method Name
Chemiluminescence
Important Note
The measured anti-Rubella IgG value of a patient’s sample can vary depending on the testing procedure used. Anti-Rubella IgG values determined on patient samples by different testing procedures cannot be directly compared with one another and could be the cause of erroneous medical interpretations. Method used Roche Elecsys Rubella IgG assay.
Aliases
Rubella IgG Antibody - Qualitative, Rubella IgG Ab - Qualitative
Specimen Required
one SST/gel tube
Specimen Minimum Volume
0.5 mL of blood
Samples should not be taken from patients receiving therapy with high biotin doses (i.e. > 5 mg/day) until at least 8 hours following the last biotin administration.
Specimen Stability Information
Separated serum is stable for up to 5days at 2 – 8°C. Freeze for extended storage.
Special Instructions
Lipemic, hemolyzed or icteric serum may interfere with the assay.
Performing Laboratory
As ordered. Turn around time four hours.
Reference Values
Results obtained with the Elecsys Rubella IgG assay can be interpreted as follows:
Non-reactive: < 10 IU/mL
Reactive: ≥ 10 IU/mL
The CLSI (Clinical and Laboratory Standards Institute) subcommittee on Rubella Serology recommended 10 IU/mL as the cutoff level.
A result < 10 IU/mL is considered to be non-reactive.
A result ≥ 10 IU/mL is considered to be positive for IgG antibody to Rubella virus. The presence of IgG antibodies to Rubella virus is an indication of previous exposure to the virus, either by prior infection or by vaccination. Patients suspected of acute Rubella infection should be tested for the presence of Rubella-specific IgM. The diagnosis of acute Rubella infection may be supported by a significant increase of the Rubella IgG antibody titer from a first to a second sample. A test result < 10 IU/mL does not completely rule out the possibility of an acute Rubella infection. Specimens taken very early in the acute phase of infection may not contain any detectable amounts of Rubella IgG antibodies or may have an antibody concentration < 10 IU/mL.
The presence of IgG antibodies in a single sample is not sufficient to distinguish between an acute or past infection.
The lack of a significant increase of the Rubella IgG antibody titer (e.g. within 3-4 weeks) may not completely exclude acute Rubella infection.
When monitoring the Rubella-specific IgG antibody titer it is recommended that serial samples be tested by parallel measurements.
The results in HIV patients, in patients undergoing immunosuppressive therapy or in patients with other disorders leading to immune suppression should be interpreted with caution.
Day(s) and Time(s) Performed
As ordered. Turn around time four hours.
Specimen Retention Time
72 hours