ARUP's Laboratory Test Directory

West Nile Virus Antibodies, IgG and IgM by ELISA, CSF : 0050228

Mnemonic: WNILE CSF

Methodology: Semi-Quantitative Enzyme-Linked Immunosorbent Assay
Performed: Tue, Fri
Reported: 1-8 days
Specimen Required: Collect: CSF.

Specimen Preparation: Transfer 2 mL CSF to an ARUP Standard Transport Tube. (Min: 0.3 mL)

Storage/Transport Temperature: Refrigerated.

Unacceptable Conditions: Contaminated, heat-inactivated, or hemolyzed specimens.

Stability (collection to initiation of testing): Ambient: 8 hours; Refrigerated: 2 weeks; Frozen: 1 year (avoid repeated freeze/thaw cycles)
Reference Interval:
Test Number Components Reference Interval
0050238West Nile Virus Antibody, IgG by ELISA, CSF 1.29 IV or less: Negative - No significant level of West Nile virus IgG antibody detected.
1.30-1.49 IV: Equivocal - Questionable presence of West Nile virus IgG antibody detected. Repeat testing in 10-14 days may be helpful.
1.50 IV or greater: Positive - Presence of IgG antibody to West Nile virus detected, suggestive of current or past infection.
0050239West Nile Virus Antibody, IgM by ELISA, CSF 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: This test is intended to be used as a semi-quantitative means of detecting West Nile virus-specific IgG and IgM in CSF specimens 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 be considered.

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.

See Compliance Statement B: www.aruplab.com/CS
CPT Code(s): 86789; 86788
Cross References: Arbovirus (West Nile Virus Antibodies, IgG & IgM by ELISA, CSF), Flavivirus (West Nile Virus Antibodies, IgG & IgM by ELISA, CSF), Mosquito borne encephalitis (West Nile Virus Antibodies, IgG & IgM by ELISA, CSF), Viral encephalitis (West Nile Virus Antibodies, IgG & IgM by ELISA, CSF)