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HelpTest Code WNMS West Nile Virus Antibody, IgM, Serum
Reporting Name
West Nile Virus Ab, IgM, SPerforming Laboratory
Mayo Clinic Laboratories in Rochester
Useful For
Detection of IgM antibodies in West Nile virus infections
Method Name
Only orderable as part of a profile. For more information see WNS / West Nile Virus Antibody, IgG and IgM, Serum.
Enzyme-Linked Immunosorbent Assay (ELISA)
Specimen Required
Only orderable as part of a profile. For more information see WNS / West Nile Virus Antibody, IgG and IgM, Serum.
Collection Container/Tube:
Preferred: Serum gel
Acceptable: Red top
Submission Container/Tube: Plastic vial
Specimen Volume: 0.5 mL
Collection Instructions: Centrifuge and aliquot serum into a plastic vial.
Specimen Type
SerumSpecimen Minimum Volume
0.4 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Serum | Refrigerated (preferred) | 14 days | |
| Frozen | 14 days |
Reject Due To
| Gross hemolysis | Reject |
| Gross lipemia | Reject |
| Gross icterus | Reject |
| Heat inactivated specimen | Reject |
Reference Values
Only orderable as part of a profile. For more information see WNS / West Nile Virus Antibody, IgG and IgM, Serum.
Negative
Reference values apply to all ages
Interpretation
Presence of specific IgM-class antibodies in a serum specimen is consistent with acute-phase infection with West Nile virus (WNV). By the 8th day of illness, most infected persons will have detectable serum IgM antibody to WNV; in most cases it will be detectable for at least 1 to 2 months following disease resolution and, in some cases, will be detectable for 12 months or longer.
The absence of IgM antibodies to WNV is consistent with lack of acute-phase infection with this virus. Specimens collected too early in the acute phase (eg, before 8-10 days postinfection) may be negative for IgM-specific antibodies to WNV. If WNV is suspected, a second specimen collected approximately 14 days postinfection should be tested.
In the very early stages of WNV infection, IgM may be detectable in cerebrospinal fluid before it becomes detectable in serum.
Day(s) Performed
Monday, Wednesday, Friday
Report Available
Same day/1 to 4 daysTest Classification
This test has been cleared, approved, or is exempt by the US 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.CPT Code Information
86788
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| WNMS | West Nile Virus Ab, IgM, S | 29567-5 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| WNMS | West Nile Virus Ab, IgM, S | 29567-5 |