Plasma

Call laboratory for additional acceptable specimen collection containers.

3.0 mL whole blood from light green top tube or TWO Microtainer^® devices.

24 hrs/day, 7 days a week, including holidays.

3 hours (upon receipt in laboratory)

Reference range and methodology changed effective 12/11/2012.

0.8 AI or less: Negative - No significant level of detectable varicella- zoster IgG antibody.

0.9-1.0 AI: Equivocal - Repeat testing in 10-14 days may be helpful.

1.1 AI or greater: Positive - IgG antibody to varicella-zoster detected, which may indicate a current or past exposure/immunization to varicella-zoster.

The best evidence for current infection is a significant change on two appropriately timed specimens, where both tests are done in the same laboratory at the same time.

Varicella-zoster IgG antibody can be formed following varicella-zoster infection or after varicella-zoster vaccination. A reactive result is consistent with immune status to varicella-zoster virus. Non-reactive and equivocal results flag as abnormal in Epic which indicates non- immune or equivocal immune status to varicella-zoster. A non-reactive result does NOT imply varicella-zoster infection. If ordered in workup of possible varicella-zoster infection, the IgG antibody results should be interpreted in conjunction with other laboratory tests, clinical history, and physical examination.

Patients with a current primary infection of varicella may not begin producing measurable concentrations of anti- varicella antibodies until several days after infection. An assay for the presence of IgM varicella antibodies may be helpful in diagnosing recent infection.

A positive test result in immunocompromised patients receiving prophylactic treatment with zoster immune serum globulin or zoster immune plasma may not be indicative of prior infection with VZV.

Multiplex Flow Immunoassay

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