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Test Code ZG205 West Nile Virus Antibodies (IgG, IgM), CSF

Additional Codes

MAYO:FWTNL


Specimen Required


Submit 2 mL spinal fluid (CSF) in a sterile, plastic screw-cap vial refrigerated.


Method Name

Enzyme Immunoassay (EIA)

Reporting Name

West Nile Virus Ab (IgG, IgM), CSF

Specimen Type

CSF

Specimen Minimum Volume

0.7 mL

Specimen Stability Information

Specimen Type Temperature Time
CSF Refrigerated (preferred) 7 days
  Frozen  30 days
  Ambient  4 days

Reference Values

Reference Range:

IgG

<1.30

 

IgM

<0.90

 

 

 

Interpretive Criteria:

 

 

IgG:

<1.30

Antibody not detected

 

1.30-1.49

Equivocal

 

≥1.50

Antibody detected

 

 

 

IgM:

<0.90

Antibody not detected

 

0.90-1.10

Equivocal

 

>1.10

Antibody detected

 

 

West Nile virus (WNV) IgM is usually detectable in CSF from WNV-infected patients with encephalitis or meningitis at the time of clinical presentation. Because IgM antibody does not readily cross the blood-brain barrier, IgM antibody in CSF strongly suggests acute central nervous system infection. WNV antibody results from CSF should be interpreted with caution. Possible complicating factors include low levels of antibody found in CSF, passive transfer of antibodies from blood, and contamination via bloody spinal taps. Antibodies induced by other flavivirus infections (e.g. Dengue virus, St. Louis encephalitis virus) may show cross-reactivity with WNV.

Day(s) and Time(s) Performed

Tuesday, Thursday, Saturday

Performing Laboratory

Quest Diagnostics Infectious Disease

CPT Code Information

86788, 86789 

LOINC Code Information

Test ID Test Order Name Order LOINC Value
FWTNL West Nile Virus Ab (IgG, IgM), CSF In Process

 

Result ID Test Result Name Result LOINC Value
Z3544 West Nile AB IgG, CSF 39572-3
Z3543 West Nile AB IgM, CSF 39573-1