West Nile Virus/St. Louis Encephalitis IgM Antibody (SS02241)

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Marshfield Clinic Public WebSite

Test Code: WNIGMSO

Overview
Ordering
Specimen
Performing
Clinical/Interpretive
Contacts
Coding

Useful For

Serodiagnosis of a recent infection with any of these agents in individuals with symptoms of arbovirus infection.

Testing will not be performed as a screening test or on patients without symptoms of WNV or SLE infection.

Specimen Requirements

Specimen Type	Preferred Container/Tube	Acceptable Container/Tube	Specimen Volume	Specimen Minimum Volume (allows for 1 repeat)
Serum	Red Top Tube (RTT) or Serum Separator Tube (SST) or CSF		1-3 mL serum or 8.5 mL SST vacutainer tube, no additives or 2 mL CSF

Specimen Type

Preferred Container/Tube

Acceptable Container/Tube

Specimen Volume

Specimen Minimum Volume
(allows for 1 repeat)

Serum

Red Top Tube (RTT) or

Serum Separator Tube (SST) or

CSF

1-3 mL serum or

8.5 mL SST vacutainer tube, no additives or

2 mL CSF

Collection Processing Instructions

CSF MUST be accompanied by serum specimen.

Specimens should be collected in the acute phase of illness.

Specimens must be stored and transported to the lab at 2-8 degrees C (refrigerated/with coolpacks), and should be received within 48 hours of collection.

Performing Laboratory Information

Performing Location	Day(s) Test Performed	Analytical Time	Methodology/Instrumentation
Wisconsin State Laboratory of Hygiene	Performed weekly	2-8 days	Microsphere Immunoassay (MIA)

Reference Lab

Wisconsin State Lab of Hygiene

Test Information

Cross-reaction may occur between the arboviruses. Negative results on a single acute phase specimen do not rule out infection, as specimen may have been obtained prior to the development of an antibody response

Reference Range Information

Reference Range
Negative: Test on single acute phase CSF or serum does not rule out infection. Lack of serological evidence of infection may reflect testing of acute phase specimen(s) obtained before development of an antibody response. Equivocal: It is recommended that a serum specimen be collected in 2-3 weeks for follow-up testing. Presumptive Positive: Serologic evidence for recent infection with West Nile virus or St. Louis Encephalitis virus. Non-Specific: It is recommended that a serum specimen be collected in 2-3 weeks for follow-up testing.

Reference Range

** Negative: Test on single acute phase CSF or serum does not rule out infection. Lack of serological evidence of infection may reflect testing of acute phase specimen(s) obtained before development of an antibody response.

** Equivocal: It is recommended that a serum specimen be collected in 2-3 weeks for follow-up testing.

** Presumptive Positive: Serologic evidence for recent infection with West Nile virus or St. Louis Encephalitis virus.

** Non-Specific: It is recommended that a serum specimen be collected in 2-3 weeks for follow-up testing.

Outreach CPTs

CPT	Modifier (if needed)	Quantity	Description	Comments
86788		1	West nile virus ab IgM
86653		1	Encephalitis St. Louis ab

Classification

The MIA test methodology was developed at the CDC and validated at WSLH. It has not been cleared or approved by the U.S. Food and Drug Administration. Testing is performed twice weekly. Please contact the laboratory for information about out-of-season arbovirus testing.

Ordering Applications

Ordering Application	Description
Cerner	West Nile Virus Confirm Assay
COM	West Nile Virus Confirm Assay
Centricity	West Nile Virus Confirm Assay
Portal	West Nile Virus Confirm Assay

If the ordering application you are looking for is not listed, contact your local laboratory for assistance.