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Lab Manual for Moffitt-Long and Mount Zion

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West Nile Virus Antibodies, Serum (IgG & IgM)

Item Value
Approval req'd? No
Available Stat? No
Test code WNVS
Test group WNV
Performed by Quest
Sendout? Yes
Method EIA
Container type Gold top, Red top
Amount to Collect 4 mL blood
Sample type Serum (see Collection Instructions)
Preferred volume 2 mL serum
Min. Volume 0.7 mL serum
Processing notes Order Quest test #36596 , freeze serum at -20C.

Note: Do not use test code WNVN (WNV NAT) or PTXID (Organ Donor Testing) when only West Nile Virus is ordered. Only use test code WNVS.
Units Index
Normal range West Nile Virus IgG:
Negative <1.30
Equivocal 1.30-1.49
Positive ≥1.50


West Nile Virus IgM:
Negative <0.90
Equivocal 0.90-1.10
Positive >1.10
Synonyms WNV
Stability Room temperature 4 days, refrigerated 1 week, frozen @ -20C 1 month, frozen @ -70C indefinite
Reflex? See 'Additional information'
Additional information West Nile Virus (WNV) IgM antibodies, in blood or CSF, are positive in most infected people within 8 days of onset of symptoms and may remain detectable for months. In our laboratory, sera with reactive IgM are rerun in a modified test to rule out nonspecific reactions. IgG antibodies indicate either current or past exposure to the virus.
CPT coding 86788-90, 86789-90
LOINC code 36897-7
Last Updated 4/3/2012 9:33:45 PM
Entry Number 1011
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