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West Nile Virus Ab, IgG and IgM, S
Test CodeWNGMS
Alias/See Also
Epic: LAB867
Mayo: WNS
Mayo: WNS
Includes
West Nile Virus Ab, IgG, S
West Nile Virus Ab, IgM, S
West Nile Serum Interpretation
Preferred Specimen
Specimen Type: Serum
Collection Container: Serum gel
Specimen Volume: 0.5 mL
Minimum Volume
0.4 mL
Other Acceptable Specimens
Collection Container: Red top
Instructions
Centrifuge and aliquot serum into a plastic vial.
Transport Container
Plastic vial
Specimen Stability
Room temperature: Undefined
Refrigerated: 14 days
Frozen: 14 days
Refrigerated: 14 days
Frozen: 14 days
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Gross hemolysis, gross lipemia, gross icterus, heat inactivated specimen
Methodology
Enzyme-Linked Immunosorbent Assay (ELISA)
Setup Schedule
Monday, Wednesday, Friday
Report Available
Same day/1 to 4 days
Reference Range
IgG: negative
IgM: negative
Reference values apply to all ages
IgM: negative
Reference values apply to all ages
Clinical Significance
USEFUL FOR
Laboratory diagnosis of infection with West Nile virus in serum specimens
TESTING ALGORITHM
The following algorithms are available in Special Instructions:
-Meningitis/Encephalitis Panel Algorithm
-Mosquito-borne Disease Laboratory Testing
CLINICAL INFORMATION
West Nile virus (WNV) is a mosquito-borne flavivirus (single-stranded RNA) that primarily infects birds but can also infect humans and horses. WNV was first isolated in 1937 from an infected person in the West Nile district of Uganda. Until the viral infection was recognized in 1999 in birds in New York City, WNV was found only in the Eastern Hemisphere, with wide distribution in Africa, Asia, the Middle East, and Europe.(1-3) In 2012, a total of 5674 cases of WNV were reported to the Centers for Disease Control and Prevention (CDC), among which 2873 (51%) were classified as neuroinvasive disease (eg, meningitis or encephalitis) and 286 (5%) cases resulted in death.(2)
Most people who are infected with WNV will not develop clinical signs of illness. It is estimated that about 20% of those who become infected will develop West Nile fever with mild symptoms, including fever, headache, myalgia, and occasionally a skin rash on the trunk of the body. Case fatality rates among patients hospitalized during recent outbreaks have ranged from 4% to 14%. Advanced age is the most important risk factor for death, and patients older than 70 years of age are at particularly high risk.(1)
Laboratory diagnosis is best achieved by demonstration of specific IgG and IgM class antibodies in serum specimens. Polymerase chain reaction (PCR) tests (WNVP / West Nile Virus (WNV), Molecular Detection, PCR, Plasma) can detect WNV RNA in plasma specimens from patients with recent WNV infection (ie, 3 to 5 days following infection) when specific antibodies to the virus are not yet present. However, the likelihood of detection is relatively low as the sensitivity of PCR detection is approximately 55% in cerebrospinal fluid and approximately 10% in blood, from patients with known WNV infection.
Laboratory diagnosis of infection with West Nile virus in serum specimens
TESTING ALGORITHM
The following algorithms are available in Special Instructions:
-Meningitis/Encephalitis Panel Algorithm
-Mosquito-borne Disease Laboratory Testing
CLINICAL INFORMATION
West Nile virus (WNV) is a mosquito-borne flavivirus (single-stranded RNA) that primarily infects birds but can also infect humans and horses. WNV was first isolated in 1937 from an infected person in the West Nile district of Uganda. Until the viral infection was recognized in 1999 in birds in New York City, WNV was found only in the Eastern Hemisphere, with wide distribution in Africa, Asia, the Middle East, and Europe.(1-3) In 2012, a total of 5674 cases of WNV were reported to the Centers for Disease Control and Prevention (CDC), among which 2873 (51%) were classified as neuroinvasive disease (eg, meningitis or encephalitis) and 286 (5%) cases resulted in death.(2)
Most people who are infected with WNV will not develop clinical signs of illness. It is estimated that about 20% of those who become infected will develop West Nile fever with mild symptoms, including fever, headache, myalgia, and occasionally a skin rash on the trunk of the body. Case fatality rates among patients hospitalized during recent outbreaks have ranged from 4% to 14%. Advanced age is the most important risk factor for death, and patients older than 70 years of age are at particularly high risk.(1)
Laboratory diagnosis is best achieved by demonstration of specific IgG and IgM class antibodies in serum specimens. Polymerase chain reaction (PCR) tests (WNVP / West Nile Virus (WNV), Molecular Detection, PCR, Plasma) can detect WNV RNA in plasma specimens from patients with recent WNV infection (ie, 3 to 5 days following infection) when specific antibodies to the virus are not yet present. However, the likelihood of detection is relatively low as the sensitivity of PCR detection is approximately 55% in cerebrospinal fluid and approximately 10% in blood, from patients with known WNV infection.
Last Updated: June 13, 2023