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Test Code WEST NILE West Nile Virus Antibody, IgG and IgM, Serum

Important Note

Mayo test code WNS

Useful For

Laboratory diagnosis of infection with West Nile virus in serum specimens

Profile Information

Test ID Reporting Name Available Separately Always Performed
WNGS West Nile Virus Ab, IgG, S No Yes
WNMS West Nile Virus Ab, IgM, S No Yes
WNVSI West Nile Serum Interpretation No Yes

Method Name

Enzyme-Linked Immunosorbent Assay (ELISA)

Reporting Name

West Nile Virus Ab, IgG and IgM, S

Specimen Type

Serum


Specimen Required


Collection Container/Tube:

Preferred: Serum gel

Acceptable: Red top

Specimen Volume: 0.5 mL


Specimen Minimum Volume

0.4 mL

Specimen Stability Information

Specimen Type Temperature Time
Serum Refrigerated (preferred) 14 days
  Frozen  14 days

Clinical Information

West Nile virus (WNV) is a mosquito-borne flavivirus (single-stranded RNA) that primarily infects birds but can also infect humans and horses. WNV was first isolated in 1937 from an infected person in the West Nile district of Uganda. Until the viral infection was recognized in 1999 in birds in New York City, WNV was found only in the Eastern Hemisphere, with wide distribution in Africa, Asia, the Middle East, and Europe.(1-3) Most recently, in 2012, a total of 5,674 cases of WNV were reported to the Centers for Disease Control and Prevention (CDC), among which 2,873 (51%) were classified as neuroinvasive disease (eg, meningitis or encephalitis) and 286 (5%) cases resulted in death.(2)

 

Most people who are infected with WNV will not develop clinical signs of illness. It is estimated that about 20% of those who become infected will develop West Nile fever with mild symptoms, including fever, headache, myalgia, and occasionally a skin rash on the trunk of the body. Case fatality rates among patients hospitalized during recent outbreaks have ranged from 4% to 14%. Advanced age is the most important risk factor for death, and patients older than 70 years of age are at particularly high risk.(1)

 

Laboratory diagnosis is best achieved by demonstration of specific IgG and IgM class antibodies in serum specimens. PCR (WNVP / West Nile Virus (WNV), Molecular Detection, PCR, Plasma) can detect WNV RNA in plasma specimens from patients with recent WNV infection (ie, 3 to 5 days following infection) when specific antibodies to the virus are not yet present. However, the likelihood of detection is relatively low as the sensitivity of PCR detection is approximately 55% in cerebrospinal fluid and approximately 10% in blood, from patients with known WNV infection.

Reference Values

IgG: Negative

IgM: Negative

Day(s) and Time(s) Performed

Monday through Friday; 9 a.m. (June through September)

Monday, Wednesday, Friday; 9 a.m. (October through May)

Analytic Time

Same day/1 day

Performing Laboratory

Mayo Medical Laboratories in Rochester

CPT Code Information

IgG-86789

IgM-86788

LOINC Code Information

Result ID Test Result Name Result LOINC Value
WNGS West Nile Virus Ab, IgG, S 29566-7
WNMS West Nile Virus Ab, IgM, S 29567-5
WNVSI West Nile Serum Interpretation 69048-7

NY State Approved

Yes

Test Classification

This test has been cleared or approved by the U.S. Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

Testing Algorithm

The following algorithms are available in Special Instructions:

-Assessment for Zika Virus Infection in Nonpregnant Individuals

-Assessment for Zika Virus Infection in Pregnant Women

Northwell Health Laboratories Additional Information:

Computer Interface Code

   PDM #  5901810