Test Catalog

Test Id : STLP

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St. Louis Encephalitis Antibody, IgG and IgM, Serum

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Overview

Test Catalog

Useful For
Suggests clinical disorders or settings where the test may be helpful

Aiding in the diagnosis of St. Louis encephalitis using serum 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.

Yes

Reporting Name
Lists a shorter or abbreviated version of the Published Name for a test

St. Louis Enceph Ab, IgG and IgM, S

Aliases
Lists additional common names for a test, as an aid in searching

Arbovirus Serology

Encephalitis Antibodies

Flavivirus (Old Arbovirus, Group B)

Saint Louis Encephalitis Antibodies

St Louis Encephalitis (SLE)

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

Serum

Ordering Guidance

This assay detects only St. Louis virus. For a complete arbovirus panel, order ARBOP / Arbovirus Antibody Panel, IgG and IgM, Serum.

Specimen Required
Defines the optimal specimen required to perform the test and the preferred volume to complete testing

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 plastic vial.

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.

0.25 mL

Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected

Gross hemolysis Reject
Gross lipemia Reject

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
Serum 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 St. Louis encephalitis using serum 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 onset of St. Louis encephalitis is characterized by generalized malaise, fever, chilliness, headache, drowsiness, nausea, and sore throat or cough followed in 1 to 4 days by the meningeal and neurologic signs. The severity of illness increases with advancing age; persons over 60 years have the highest frequency of encephalitis. Symptoms of irritability, sleeplessness, depression, memory loss, and headaches can last up to 3 years. Areas of outbreaks since 1933 have involved the western United States, Texas, the Ohio-Mississippi Valley, and Florida. The vector of transmission is the mosquito. Peak incidence of St. Louis encephalitis is associated with summer and early autumn.

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: <1:10

IgM: <1:10

Reference values apply to all ages.

Interpretation
Provides information to assist in interpretation of the test results

In patients infected with the St. Louis encephalitis virus, IgG antibody is generally detectable within 1 to 3 weeks of onset, peaking within 1 to 2 months, and declining slowly thereafter.

 

IgM class antibody is also reliably detected within 1 to 3 weeks of onset, peaking and rapidly declining within 3 months.

 

A single serum specimen IgG of 1:10 or greater indicates exposure to the virus. Results from a single serum specimen can differentiate early (acute) infection from past infection with immunity if IgM is positive (suggests acute infection). While a 4-fold or greater rise in IgG antibody titer in acute and convalescent sera indicates recent infection.

 

Infections with St. Louis encephalitis can occur at any age. The age distribution depends on the degree of exposure to the particular transmitting arthropod relating to age and sex, as well as the occupational, vocational, and recreational habits of the individuals. St. Louis encephalitis tends to produce the most severe clinical infections in older persons.

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.

 

Specimens collected within the first 2 weeks after onset are variably negative for IgG antibody and should not be used to exclude the diagnosis of St. Louis encephalitis (SLE). If SLE is suspected, a second specimen should be collected and tested 10 to 21 days later.

 

Since cross-reactivity with dengue fever does occur with SLE antigens and, therefore, cannot be differentiated further. The specific virus responsible for such a titer may be deduced by the travel history of the patient, along with available medical and epidemiological data, unless the virus can be isolated.

 

Usually, when an infection with an arbovirus is suspected, it is too late to isolate the virus or draw serum specimens to detect a rise of antibody titer.

Clinical Reference
Recommendations for in-depth reading of a clinical nature

1. Gonzalez-Scarano F, Nathanson N: Bunyaviruses. In: Fields BN, Knipe DM, eds. Fields Virology. Vol 1. 2nd ed. Raven Press; 1990:1195-1228

2. Donat JF, Rhodes KH, Groover RV, Smith TF: Etiology and outcome in 42 children with acute nonbacterial meningoencephalitis. Mayo Clin Proc. 1980 Mar;55(3):156-160

3. Tsai TF: Arboviruses. In: Murray PR, Baron EJ, Pfaller MA, et al, eds. Manual of Clinical Microbiology. 7th ed. American Society for Microbiology; 1999:1107-1124

4. Calisher CH: Medically important arboviruses of the United States and Canada. Clin Microbiol Rev. 1994 Jan;7(1):89-116

5. Diaz A, Coffey LL, Burkett-Cadena N, Day JF: Reemergence of St. Louis Encephalitis Virus in the Americas. Emerg Infect Dis. 2018 Dec;24(12):2150-2157. doi: 10.3201/eid2412.180372

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 serum 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 serum 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. 02, 05/01/2018)

PDF Report
Indicates whether the report includes an additional document with charts, images or other enriched information

No

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.

Monday through Friday (May through October)

Monday, Wednesday, Friday (November through April)

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.

Same day/1 to 4 days

Specimen Retention Time
Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded

2 weeks

Performing Laboratory Location
Indicates the location of the laboratory that performs the test

Rochester

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 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
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.

86653 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
STLP St. Louis Enceph Ab, IgG and IgM, S 96255-5
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.
8182 St. Louis Enceph Ab, IgG, S In Process
87268 St. Louis Enceph Ab, IgM, S In Process

Test Setup Resources

Setup Files
Test setup information contains test file definition details to support order and result interfacing between Mayo Clinic Laboratories and your Laboratory Information System.

Excel | Pdf

Sample Reports
Normal and Abnormal sample reports are provided as references for report appearance.

Normal Reports | Abnormal Reports

SI Sample Reports
International System (SI) of Unit reports are provided for a limited number of tests. These reports are intended for international account use and are only available through MayoLINK accounts that have been defined to receive them.

SI Normal Reports | SI Abnormal Reports