ARUP's Laboratory Test Directory
| 0050239: West Nile Virus Antibody, IgM by ELISA, CSF |
| Test Mnemonic: WNIL IGM | |
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Methodology: Enzyme-Linked Immunosorbent Assay
Performed: Tue, Fri Reported: 1-8 days |
| Specimen Required: | |
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Collect: CSF.
Transport: 2 mL CSF at 2-8°C. (Min: 0.5 mL) Submit specimen in an ARUP Standard Transport Tube. Pediatric Collection/Transport: 0.15 mL CSF at 2-8°C. Unacceptable Conditions: Heat-inactivated, contaminated, or hemolyzed specimens. Stability: Ambient: 8 hours; Refrigerated: 2 weeks; Frozen: 1 year (avoid repeated freeze/thaw cycles) |
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| Reference Interval: |
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0.89 IV or less: Negative - No significant level of West Nile virus IgM antibody detected. 0.90-1.10 IV: Equivocal - Questionable presence of West Nile virus IgM antibody detected. Repeat testing in 10-14 days may be helpful. 1.11 IV or greater: Positive - Presence of IgM antibody to West Nile virus detected, suggestive of current or recent infection. |
| Interpretive Data: | |
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This test is intended to be used as a semi-quantitative means of detecting West Nile virus-specific IgM in CSF samples in which there is a clinical suspicion of West Nile virus infection. This test should not be used solely for quantitative purposes, nor should the results be used without correlation to clinical history or other data. Because other members of the Flaviviridae family, such as St. Louis encephalitis virus, show extensive cross-reactivity with West Nile virus, serologic testing specific for these species should also be performed. The detection of antibodies to West Nile virus in cerebrospinal fluid may indicate central nervous system infection. However, consideration must be given to possible contamination by blood or transfer of serum antibodies across the blood-brain barrier. Please refer to Statement E in the Compliance Statements section in the front of the Laboratory Test Directory. |
| CPT Code(s): | |
| 86788 |