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Test Code LCWNV West Nile Virus, Molecular Detection, PCR, Spinal Fluid

Reporting Name

West Nile Virus PCR

Useful For

Rapid testing for West Nile virus (WNV) RNA

 

An adjunctive test to serology for detection of early WNV infection

 

This assay should not be used for screening asymptomatic individuals and should only be used to test patients with signs and symptoms of West Nile virus (WNV) disease.

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

CSF


Specimen Required


Container/Tube: Sterile vial

Specimen Volume: 0.5 mL

Collection Instructions: Do not centrifuge.


Specimen Minimum Volume

0.3 mL

Testing Algorithm

The following algorithms are available in Special Instructions:

-Meningitis/Encephalitis Panel Algorithm

-Mosquito-borne Disease Laboratory Testing

Specimen Stability Information

Specimen Type Temperature Time Special Container
CSF Refrigerated (preferred) 7 days
  Frozen  7 days

Reference Values

Negative

Day(s) and Time(s) Performed

Monday through Saturday; Continuously 7 a.m.-8 p.m. (June through November)

Monday, Wednesday, Friday; 6 a.m. (December through May)

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.

CPT Code Information

87798

LOINC Code Information

Test ID Test Order Name Order LOINC Value
LCWNV West Nile Virus PCR 34461-4

 

Result ID Test Result Name Result LOINC Value
SS013 Specimen Source 31208-2
86197 West Nile Virus PCR 34461-4

Clinical Reference

1. Petersen LR, Brault AC, Nasci RS: West Nile Virus: Review of the Literature. JAMA 2013;310(3):308-315

2. Busch MP, Tobler LH, Saldanha J, et al: Analytical and clinical sensitivity of West Nile virus RNA screening and supplemental assays available in 2003. Transfusion 2005;5(4):492-499

3. New York City Department of Health. West Nile surveillance and control: an update for healthcare providers in New York City. City Health Information. June 2001;20(2)

Method Description

This LightCycler PCR assay has been optimized to detect common conserved sequences in the nonstructural protein of West Nile virus (WNV). Viral nucleic acid is extracted by the MagNA Pure automated instrument (Roche Applied Science) from cerebrospinal, or plasma. Primers directed to the nonstructural protein amplify a specific sequence of the virus. For the test, WNV genomic RNA is transcribed to cDNA. The LightCycler instrument amplifies and monitors the development of target nucleic acid sequences after the annealing step during PCR cycling by fluorescence assay. This automated PCR system utilizes stringent air-controlled temperature cycling and capillary cuvettes to rapidly detect (30-40 minutes) amplicon development. The detection of amplified products is based on the fluorescence resonance energy transfer (FRET) principle. For FRET product detection, a hybridization probe with a donor fluorophore, fluorescein, on the 3'-end is excited by an external light source and emits light that is absorbed by a second hybridization probe with an acceptor fluorophore, LC-Red 640, at the 5'-end. The acceptor fluorophore then emits a light of a different wavelength that can be measured with a signal that is proportional to the amount of specific PCR product. Analysis of the PCR amplification and probe melting curves are accomplished through the use of LightCycler software.(Cockerill FR III, Uhl JR: Applications and challenges of real-time PCR for the clinical microbiology laboratory. In Rapid Cycle Real-Time PCR Methods and Applications. Edited by U Reischel, C Wittwer, F Cockerill. Berlin, Germany, Springer-Verlag; 2002, pp3-30)

Analytic Time

Monday through Thursday: 2 days Friday, Saturday: 3 days

Reject Due To

All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.

Method Name

Real-Time Polymerase Chain Reaction (PCR)/RNA Probe Hybridization

Forms

If not ordering electronically, complete, print, and send a Microbiology Test Request (T244) with the specimen.

Secondary ID

86197