Clinics and Departments

Laboratory Services

Lab Dept:

Serology

Test Name:

ARBOVIRUS & WEST NILE ANTIBODY PANEL, CSF

General Information

Lab Order Codes:

AWNC

Synonyms:

Encephalitis Antibody; Arbovirus Antibody; Encephalitis LaCrosse/California IgM Antibody; Encephalitis Eastern Equine IgM Antibody; Encephalitis St. Louis Equine IgM Antibody; Encephalitis Western Equine IgM Antibody, Encephalitis LaCrosse/California IgG Antibody; Encephalitis Eastern Equine IgG Antibody; Encephalitis St. Louis Equine IgG Antibody; Encephalitis Western Equine IgG Antibody; West Nile Virus; WNV Ab

CPT Codes:

86651 x2 – Antibody; encephalitis, California
86652 x2 – Antibody; encephalitis, Eastern equine
86653 x2 – Antibody; encephalitis, St. Louis equine
86654 x2 – Antibody; encephalitis, Western equine
86778 - West Nile Virus, IgM
86779 - West Nile Virus, IgG

Test Includes:

IgM and IgG antibody determinations for 4 different encephalitis strains and West Nile Virus in spinal fluid.

Logistics

Test Indications:

Useful for detecting antibodies to Eastern equine encephalitis virus, LaCrosse/California encephalitis virus, St. Louis equine encephalitis virus, and Western equine encephalitis, aiding a diagnosis arboviral encephalitis or West Nile Virus.

Lab Testing Sections:

Serology - Sendouts

Referred to:

Mayo Medical Laboratories (MML Test: 87813/AWNC)

Phone Numbers:

MIN Lab: 612-813-6280

STP Lab: 651-220-6550

Test Availability:

Daily, 24 hours

Turnaround Time:

1-4 days, performed Monday - Friday

Special Instructions:

When this test is ordered, it is recommended that both blood and spinal fluid be collected. See Arbovirus & West Nile Ab, Blood for blood collection and other test information.

Specimen

Specimen Type:

CSF

Container:

CSF conical tube

Draw Volume:

0.8 mL (Minimum: 0.6 mL) spinal fluid

Collection:

Routine CSF collection

Special Processing:

Lab Staff: Aliquot 0.75 mL spinal fluid into a sterile, screw-capped, round bottom, plastic vial. Store and ship at refrigerated temperatures.

Patient Preparation:

None

Sample Rejection:

Room temperature specimens; mislabeled or unlabeled specimens; gross hemolysis; gross lipemia

Interpretive

Reference Range:

Reference ranges apply to all ages.

California (LaCrosse) Encephalitis Antibody

IgG:

<1:10

IgM:

<1:10

Eastern Equine Encephalitis Antibody

IgG:

<1:10

IgM:

<1:10

St. Louis Encephalitis Antibody

IgG:

<1:10

IgM:

<1:10

Western Equine Encephalitis

IgG:

<1:10

IgM:

<1:10

West Nile Virus

IgG:

Negative

IgM:

Negative

Critical Values:

N/A

Limitations:

Arbovirus Ab, CSF: 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 blood-brain barrier, or by the introduction of blood into the CSF collection. Since cross-reactivity with dengue fever virus does occur with St. Louis encephalitis antigens, and, therefore, cannot be differentiated further, the specific virus responsible for positive results may be deduced by the travel history of the patient, along with available medical and epidemiological data, unless the virus can be isolated.

Eastern Equine Encephalitis and Western Equine Encephalitis viruses show some cross-reactivity; however, antibody responses to the infecting virus is typically at least 8-fold higher.

West Nile Virus Ab, CSF: Test results should be used in conjunction with a clinical evaluation and other available diagnostic procedures. The significance of negative test results in immunosuppressed patients is uncertain. False-negative results due to competition by high levels of IgG, while theoretically possible, have not been observed. WNV antibody results for CSF should be interpreted with caution. Complicating factors include low antibody levels found in CSF, passive transfer of antibody from blood, and contamination via bloody taps.

Methodology:

Arbovirus, CSF: Immunofluorescence Assay (IFA)
West Nile Virus, CSF: Enzyme-Linked Immunosorbent Assay (ELISA)

References:

Mayo Medical Laboratories June 2013



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