West Nile Virus by PCR (Sendout)

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General Information

Lab Name
West Nile Virus by PCR
Lab Code
RWNVP
Epic Name
West Nile Virus PCR (Sendout)
External Test Id
WNVS
Description

Useful For:

  • Rapid testing for West Nile virus (WNV) RNA (lineage 1 and lineage 2) using serum specimens

  • An adjunctive test to serology for detection of early WNV infection (ie, first few days after symptom onset)

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

Testing Algorithm:

Synonyms
Arbovirus, Flavivirus, Mosquito Borne Encephalitis, Viral encephalitis, West Nile PCR, WNV, WNVS
Components
Code Name
RWNVPR West Nile Virus by PCR

Interpretation

Guidelines
Method

Real-Time Polymerase Chain Reaction (PCR)

Reference Range
See individual components
Ref. Range Notes

Reference Values: Negative

Interpretation: A positive result indicates the presence of West Nile virus (WNV) RNA and is consistent with early WNV infection.

Interferences and Limitations

Cautions:

The sensitivity of the assay is very dependent upon the time of illness onset in which the specimen is collected. Polymerase chain reaction testing has the greatest utility when used within the first few days of symptom onset.

Whole blood rather than serum has been shown to provide increased sensitivity for detecting West Nile virus (WNV) RNA.

A negative test does not exclude infection with WNV. Therefore, the results obtained should be used in conjunction with clinical findings and serologic test results to make an accurate diagnosis.

This assay detects both viable and nonviable virus. Test performance depends on viral load in the specimen and may not correlate with cell culture performed on the same specimen.

Ordering & Collection

Specimen Type
Blood
Collection

Collect 3 mL blood in GOLD TOP SST or RED TOP tube

Handling Instructions

Outside Laboratories: Centrifuge sample and transfer serum to a separate sterile vial within 6 hours of collection. Refrigerate serum.

Stability: Refrigerated (preferred): 7 days; Frozen: 7 days; Ambient: Unacceptable.

Reject Due To: Gross hemolysis, heat-inactivated specimen.

Quantity
Requested: 0.5 mL serum
Minimum: 0.3 mL serum

Processing

Receiving Instructions

Centrifuge sample and transfer serum to a separate sterile vial within 6 hours of collection. Refrigerate serum.

Sendouts:

  • Order Mayo Test: WNVS.
  • Interfaced: Yes.

Stability: Refrigerated (preferred): 14 days; Frozen: 30 days; Ambient: Unacceptable.

Reject Due To: Gross hemolysis, heat-inactivated specimen.

Misc Sendout

Performance

Lab Department
Sendouts Mayo Lab (RF)(MARF)
Frequency
Performed: Monday - Friday. Report Available: 1-5 days.
Available STAT?
No
Performing Location(s)
Sendout Mayo Clinic Laboratories
800-533-1710

200 First Street Southwest
Rochester, MN 55901

Billing & Coding

CPT Codes
87798
LOINC
34892-0
Interfaced Order Code
UOW3531