West Nile Virus (WNV) Antibody, IgG and IgM

TEST: 138842
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CPT: 86788; 86789
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Synonyms

  • Flavivirus
  • Mosquito-borne
  • Vectorborne
  • West Nile Virus, IgG and IgM
  • West Nile Virus, Serology
  • WNV Antibody

Expected Turnaround Time

1 - 4 days

Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.

Related Documents

Specimen Requirements

Specimen

Serum

Volume

1 mL

Minimum Volume

0.5 mL

Container

Red-top tube or gel-barrier tube

Storage Instructions

Room temperature

Stability Requirements

Temperature

Period

Room temperature

16 days

Refrigerated

16 days

Frozen

16 days

Freeze/thaw cycles

Stable x4

Causes for Rejection

Gross contamination; severe hemolysis; icteric serum; lipemic serum; quantity not sufficient for analysis

Test Details

Use

This test is indicated for use as an aid to the diagnosis of West Nile virus encephalitis. WNV IgM antibodies typically appear three to eight days after illness onset and persist 30 to 90 days (but can persist up to 500 days). WNV IgG antibodies appear shortly after IgM antibodies and persist greater than 500 days. Due to cross-reactivity with other flaviviruses, confirmation by neutralizing antibody assay may be recommended.

Limitations

The performance of this assay has not been established for screening the general population. Testing should only be performed on patients with clinical symptoms consistent with WNV encephalitis. Serological cross-reactivity across the flavivirus group is common (i.e., between Dengue virus, Japanese encephalitis virus, St. Louis encephalitis virus, yellow fever virus and others).

Methodology

Enzyme immunoassay (EIA)

Reference Interval

Negative

References

Tardei G, Ruta S, Chitu V, Tardei G, Ruta S, Chitu V, Rossi C, Tsai TF, Cernescu C. Evaluation of immunoglobulin M (IgM) and IgG enzyme immunoassays in serologic diagnosis of West Nile virus infection. J Clin Microbiol. 2000 Jun;38(6):2232-2239.10834982
West Nile Virus: Diagnostic Testing. Centers for Disease Control and Prevention (CDC) website: https://www.cdc.gov/westnile/healthcareproviders/healthCareProviders-Diagnostic.html. Updated April 2023. Accessed October 2023.

LOINC® Map

Order Code Order Code Name Order Loinc Result Code Result Code Name UofM Result LOINC
138842 West Nile Virus Antibody,Serum 94854-7 139037 West Nile Virus, IgG 29566-7
138842 West Nile Virus Antibody,Serum 94854-7 139038 West Nile Virus, IgM 29567-5

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