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HelpTest Code WNC West Nile Virus Antibody, IgG and IgM, Spinal Fluid
Reporting Name
West Nile Virus Ab, IgG and IgM,CSFUseful For
Aiding in diagnosis of central nervous system infection with West Nile virus
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Specimen Type
CSFSpecimen Required
Supplies: Aliquot Tube, 5 mL (T465)
Collection Container/Tube: Sterile vial
Submission Container/Tube: Plastic vial
Specimen Volume: 1 mL
Specimen Minimum Volume
0.8 mL
Testing Algorithm
The following algorithms are available in Special Instructions:
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| CSF | Refrigerated (preferred) | 7 days | |
| Frozen | 30 days |
Special Instructions
Reference Values
IgG: Negative
IgM: Negative
Reference values apply to all ages.
Day(s) and Time(s) Performed
Monday, Wednesday, Friday; 9 a.m.
Test Classification
This test has been modified from the manufacturer's instructions. Its performance characteristics were determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.CPT Code Information
IgG: 86789
IgM: 86788
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| WNC | West Nile Virus Ab, IgG and IgM,CSF | 94853-9 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| WNGC | West Nile Virus Ab, IgG, CSF | 77953-8 |
| WNMC | West Nile Virus Ab, IgM, CSF | 29569-1 |
| WNVCI | West Nile CSF Interpretation | 69048-7 |
Clinical Reference
1. Petersen LR, Marafin AA: West Nile Virus: a primer for the clinician. Ann Intern Med. 2002;137:173-179
2. Centers for Disease Control and Prevention (CDC): West Nile virus and other arboviral diseases-United States, 2012. MMWR Morb Mortal Wkly Rep. 2013;62(25):513-517
3. Brinton MA: The molecular biology of West Nile Virus: a new invader of the western hemisphere. Ann Rev Microbiol. 2002;56:371-402
4. Centers for Disease Control and Prevention (CDC): Provisional surveillance summary of the West Nile virus epidemic. United States, January-November 2002. MMWR Morb Mortal Wkly Rep. 2002;51(50):1129-1133
5. Centers for Disease Control and Prevention (CDC): Investigations of West Nile virus infections in recipients of blood transfusions. MMWR Morb Mortal Wkly Rep. 2002;51(43):973-974
Method Description
IgG:
Polystyrene microwells are coated with recombinant West Nile virus (WNV) antigen. Diluted serum specimens and controls are incubated in the wells to allow specific antibody present in the specimens to react with the antigen. Nonspecific reactants are removed by washing, and peroxidase-conjugated antihuman IgG is added and reacts with specific IgG. Excess conjugate is removed by washing. Enzyme substrate and chromogen are added, and the color is allowed to develop. After adding the Stop reagent, the resultant color change is quantified by a spectrophotometric reading of optical density (OD). Specimen OD readings are compared with reference cutoff readings to determine results.(Package insert: Flavivirus [West Nile] ELISA IgG. Focus Technologies;10/16/2012)
IgM:
Polystyrene microwells are coated with the antihuman antibody specific for IgM (u-chain). Diluted serum specimens and controls are incubated in the wells, and IgM present in the specimen binds to the antihuman antibody (IgM specific) in the wells. Nonspecific reactants are removed by washing. WNV antigen is then added to the wells and incubated. If anti-WNV IgM is present in the specimen, the WNV antigen binds to the anti-WNV in the well. Unbound WNV antigen is then removed by washing the well. Mouse anti-flavivirus conjugated with horseradish peroxidase (HRP) is then added to the wells and incubated. If WNV antigen has been retained in the well by the anti-flavivirus in the specimen, the mouse anti-flavivirus: HRP binds to WNV antigen in the wells. Excess conjugate is removed by washing. Enzyme substrate and chromogen are added, and the color is allowed to develop. After adding the Stop reagent, the resultant color change is quantified by a spectrophotometric reading of OD that is directly proportional to the amount of antigen-specific IgM present in the specimen. Specimen OD readings are compared with reference cutoff OD readings to determine results.(Package insert: Flavivirus [West Nile] IgM Capture ELISA. Focus Technologies;06/01/2015)
Analytic Time
Same day/1 dayReject Due To
| Gross hemolysis | Reject |
Method Name
Enzyme-Linked Immunosorbent Assay (ELISA)
Forms
If not ordering electronically, complete, print, and send a Microbiology Test Request (T244) with the specimen.
Profile Information
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| WNGC | West Nile Virus Ab, IgG, CSF | No | Yes |
| WNMC | West Nile Virus Ab, IgM, CSF | No | Yes |
| WNVCI | West Nile CSF Interpretation | No | Yes |