Test Id : WEEPC
Western Equine Encephalitis Antibody Panel, IgG and IgM, Spinal Fluid
Useful For
Suggests clinical disorders or settings where the test may be helpful
Aiding in the diagnosis of Western equine encephalitis using spinal fluid specimens
Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.
For more information see Mosquito-borne Disease Laboratory Testing.
Method Name
A short description of the method used to perform the test
Immunofluorescence Assay (IFA)
NY State Available
Indicates the status of NY State approval and if the test is orderable for NY State clients.
Reporting Name
Lists a shorter or abbreviated version of the Published Name for a test
Aliases
Lists additional common names for a test, as an aid in searching
Alphavirus (Old Arbovirus, Group A)
Arbovirus Serology
Encephalitis Antibodies
Western Equine Encephalitis (WEE)
Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.
For more information see Mosquito-borne Disease Laboratory Testing.
Specimen Type
Describes the specimen type validated for testing
CSF
Ordering Guidance
This assay detects Western equine antibodies only. For a complete arbovirus panel, order ABOPC / Arbovirus Antibody Panel, IgG and IgM, Spinal Fluid.
New York State clients: This test is not available for specimens originating in New York.
Specimen Required
Defines the optimal specimen required to perform the test and the preferred volume to complete testing
Container/Tube: Sterile vial
Specimen Volume: 0.8 mL
Collection Instructions: Submit specimen from collection vial number 2 (preferred), 3, or 4.
Special Instructions
Library of PDFs including pertinent information and forms related to the test
Forms
If not ordering electronically, complete, print, and send Infectious Disease Serology Test Request (T916) with the specimen.
Specimen Minimum Volume
Defines the amount of sample necessary to provide a clinically relevant result as determined by the testing laboratory. The minimum volume is sufficient for one attempt at testing.
0.7 mL
Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected
| Gross hemolysis | OK |
| Gross lipemia | OK |
Specimen Stability Information
Provides a description of the temperatures required to transport a specimen to the performing laboratory, alternate acceptable temperatures are also included
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| CSF | Refrigerated (preferred) | 14 days | |
| Frozen | 14 days |
Useful For
Suggests clinical disorders or settings where the test may be helpful
Aiding in the diagnosis of Western equine encephalitis using spinal fluid specimens
Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.
For more information see Mosquito-borne Disease Laboratory Testing.
Clinical Information
Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
The virus that causes Western equine encephalitis (WEE) is widely distributed throughout the United States and Canada; disease occurs almost exclusively in the western states and Canadian provinces. The relative absence of the disease in the eastern United States probably reflects a paucity of the vector mosquito species, Culex tarsalis, and, possibly, a lower pathogenicity of local virus strains.
The disease usually begins suddenly with malaise, fever, and headache, often with nausea and vomiting. Vertigo, photophobia, sore throat, respiratory symptoms, abdominal pain, and myalgia are also common. Over a few days, the headache intensifies; drowsiness and restlessness may merge into a coma in severe cases. The onset may be more abrupt in infants and children than for adults. WEE should be suspected in any case of febrile central nervous system (CNS) disease from an endemic area. Infants are highly susceptible to CNS disease, and about 20% of cases are patients under 1 year of age. There is an excess of male patients with WEE clinical encephalitis, averaging about twice the number of infections detected in female patients. After recovery from the acute disease, patients may require several months to 2 years to overcome the fatigue, headache, and irritability. Infants and children are at a higher risk of permanent brain damage after recovery than adults.
Infections with arboviruses can occur at any age. The age distribution depends on the degree of exposure to the particular transmitting arthropod relating to age, sex, and occupational, vocational, and recreational habits of the individuals. Once humans have been infected, the severity of the host response may be influenced by age. WEE tends to produce the most severe clinical infections in young persons.
Reference Values
Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
IgG: <1:1
IgM: <1:1
Interpretation
Provides information to assist in interpretation of the test results
Detection of organism-specific antibodies in the spinal fluid (CSF) may suggest central nervous system (CNS) infection. However, these results are unable to distinguish between intrathecal antibodies and serum antibodies introduced into the CSF at the time of lumbar puncture or from a breakdown in the blood-brain barrier. The results should be interpreted with other laboratory and clinical data prior to a diagnosis of CNS infection.
Cautions
Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
All results must be correlated with clinical history and other data available to the attending physician.
False-positive results may be caused by breakdown of the blood-brain barrier, or by the introduction of blood into the spinal fluid at collection.
Western equine encephalitis and Eastern equine encephalitis viruses show some cross-reactivity; however, antibody response to the infecting virus is typically at least 8-fold higher.
Clinical Reference
Recommendations for in-depth reading of a clinical nature
1. Markoff L: Alphaviruses (Chikungunya, Eastern equine encephalitis). In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 9th ed. Elsevier; 2020:1997-20062
2. Piantadosi A, Kanjilal S: Diagnostic approach for arboviral infections in the United States. J Clin Microbiol. 2020;58(12):e01926-19. doi:10.1128/JCM.01926-19
Method Description
Describes how the test is performed and provides a method-specific reference
The indirect immunofluorescent antibody (IFA) assay is a 2-stage “sandwich" procedure. In the first stage, the patient spinal fluid (CSF) is diluted in Pretreatment Diluent for IgM and phosphate buffered saline (PBS) for IgG, added to appropriate slide wells in contact with the substrate, and incubated. Following incubation, the slide is washed in PBS, which removes unbound CSF antibodies. In the second stage, each antigen well is overlaid with fluorescein-labeled antibody to IgM and IgG. The slide is incubated allowing antigen-antibody complexes to react with the fluorescein-labeled anti-IgM and anti-IgG. After the slide is washed, dried, and mounted, it is examined using fluorescence microscopy. Positive reactions appear as cells exhibiting bright apple-green cytoplasmic fluorescence against a background of red negative control cells. Semi-quantitative endpoint titers are obtained by testing serial dilutions of positive specimens. (Package inserts: Arbovirus IFA IgM and Arbovirus IFA IgG Instructions for Use. Focus Diagnostics; Rev 03, 02/17/2023)
PDF Report
Indicates whether the report includes an additional document with charts, images or other enriched information
Day(s) Performed
Outlines the days the test is performed. This field reflects the day that the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time before the test is performed. Some tests are listed as continuously performed, which means that assays are performed multiple times during the day.
May through October: Monday through Friday
November through April: Monday, Wednesday, Friday
Report Available
The interval of time (receipt of sample at Mayo Clinic Laboratories to results available) taking into account standard setup days and weekends. The first day is the time that it typically takes for a result to be available. The last day is the time it might take, accounting for any necessary repeated testing.
Specimen Retention Time
Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Performing Laboratory Location
Indicates the location of the laboratory that performs the test
Fees :
Several factors determine the fee charged to perform a test. Contact your U.S. or International Regional Manager for information about establishing a fee schedule or to learn more about resources to optimize test selection.
- Authorized users can sign in to Test Prices for detailed fee information.
- Clients without access to Test Prices can contact Customer Service 24 hours a day, seven days a week.
- Prospective clients should contact their account representative. For assistance, contact Customer Service.
Test Classification
Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR) product.
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.
CPT Code Information
Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Clinic Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
CPT codes are provided by the performing laboratory.
CPT codes are provided by the performing laboratory.
86654 x 2
LOINC® Information
Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the order and results codes of this test. LOINC values are provided by the performing laboratory.
| Test Id | Test Order Name | Order LOINC Value |
|---|---|---|
| WEEPC | West Equine Enceph Ab Panel, CSF | 69036-2 |
| Result Id | Test Result Name |
Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
|
|---|---|---|
| 26371 | West Equine Enceph Ab, IgG, CSF | 9315-3 |
| 26372 | West Equine Enceph Ab, IgM, CSF | 9316-1 |