West Nile Virus Antibodies (IgG,IgM), ELISA, Serum [36596X]

Test Code

Alias/See Also

CPT Codes
86788, 86789

Preferred Specimen
1 mL serum

Minimum Volume
0.7 mL

Transport Container
Transport tube

Transport Temperature
Refrigerated (cold packs)

Specimen Stability
Room temperature: 4 days
Refrigerated: 7 days
Frozen: 30 days

Enzyme Immunoassay (EIA)

Setup Schedule
Set up; Mon, Wed, Fri a.m.; Report available: Next day

Cross reactivity has been observed between alphavirus group and flavivirus group, e.g., yellow fever or yellow fever vaccination.

Reference Range
West Nile Virus Ab (IgG) <1.30
West Nile Virus Ab (IgM) <0.90

Interpretive Criteria
WNV Ab (IgG)
<1.30 Antibody not detected
1.30-1.49 Equivocal
≥1.50 Antibody detected
WNV Ab (IgM)
<0.90 Antibody not detected
0.90-1.10 Equivocal
>1.10 Antibody detected

Clinical Significance
The West Nile Virus (WNV) is a single-stranded RNA virus of the Flaviviridae family. Like other arboviruses (e.g., St. Louis Encephalitis, Dengue Fever, and Yellow Fever), its main route of transmission to humans is through mosquitoes (primarily culex species) that have acquired the virus from infected birds. A single elevated WNV result, including IgM that may persist for many months, could represent past infection with WNV or infection with another flavivirus including Dengue and St. Louis Encephalitis. Diagnosis of suspected WNV infection is confirmed by isolation of WNV or detection of WNV antigen or nucleic acid sequences in clinical samples or detection of WNV-specific IgM in blood or spinal fluid, confirmed with detection of WNV-specific neutralizing antibody in the same or a subsequent sample.

See West Nile Virus: Detection with Immunologic and RT-PCR Assays in the Infectious Disease chapter, Interpretive Information section.

Performing Laboratory
Quest Diagnostics Nichols Institute
14225 Newbrook Drive
Chantilly, VA 20153

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.