Rubella Immune Status Viral Serology

The FDA-approved LIAISON® Rubella IgG Assay is used for the qualitative detection of IgG antibodies against the Rubella virus in human serum. Results are reported in IU/mL for informational reference only and are not intended for quantitative interpretation.

The cutoff value (Index = 1) is set at 10 IU/mL, based on calibration traceability to the WHO 1st International Standard for anti-Rubella Immunoglobulin, Human (1997). This follows CLSI guideline I/LA6-A, which recommends 10 IU/mL as the indicator of immune status.

Note: The stated linearity of the assay corresponds to an index value between 0 and 33, equivalent to 0–330 IU/mL. For values greater than 330 IU/mL, the assay is no longer linear, and results are reported as >330 IU/mL. The assay’s linearity has not been verified by the UW Virology Lab.

Blood: 5 mL blood in GOLD TOP serum separator tube (SST).

Also acceptable: 5 mL blood in ORANGE TOP rapid serum tube (RST) or RED TOP tube.

Blood: Harvest serum from whole blood within 24 hours of collection. Serum may be stored at 2-8°C (ice pack) for up to 7 days. Freeze at -20°C or colder for long term storage. Do not freeze/thaw.

Outside Laboratories: Store samples at 2–8°C and ship with an ice pack. Shipment time must not exceed 7 days from the collection date. Samples stored at 2–8°C for more than 7 days will be rejected.

If the time from collection to receipt at the University of Washington will exceed 7 days, ship samples on dry ice. Do not freeze/thaw samples.

Unacceptable samples: Cord blood, neonatal specimens, cadaver specimens, heat-inactivated specimens, or body fluids such as saliva, urine, amniotic fluid, pleural fluid or plasma. Specimens with obvious microbial contamination, lipemic or are grossly hemolyzed.