Serum or plasma concentration of viral RNA (e.g., West Nile virus)
This test detects genetic material from the West Nile virus in your blood or plasma. It helps identify if you’ve recently been exposed to the virus, which can cause serious illness.
["A positive result may indicate recent infection requiring medical evaluation."]
Key facts at a glance
- LOINC
- 109720-3
- Short code
- WNV Ab Msmt CSF
- Synonyms
- WNV Ab Msmt CSF
- Category
- chemistry
- Sample
- csf
- Container
- Sterile tube
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Specimen volume
- 1-2 mL
- Stability
- Immediate analysis required, Refrigerated: 1h
- Hemolysis max
- 200
- TAT
- 4–24 hours
- Order
- routine
What This Test Measures
The test looks for West Nile virus RNA, a fragment of its genetic code, in your blood or plasma. This RNA is present during the early stages of infection but typically disappears as the body fights the virus. The test is most useful shortly after exposure, often within the first week of symptoms.
Why It’s Done
Your healthcare provider may order this test if you’ve had symptoms like fever, headache, body aches, or neurological issues (e.g., confusion, muscle weakness) and suspect West Nile virus exposure, such as from mosquito bites or travel to areas with active virus transmission.
When to Expect Results
Results are usually available within 24 to 72 hours after testing. If you’re at high risk (e.g., elderly, immunocompromised), your provider may recommend follow-up testing if initial results are unclear.
What to Expect During the Test
A small blood sample is drawn from a vein in your arm. The process is quick and typically painless, though you may feel a brief pinch. The blood is then sent to a lab for analysis.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
A positive test confirms recent West Nile virus infection and may prompt treatment or monitoring for complications like meningitis or encephalitis. A negative result doesn’t always mean you’re safe—exposure could still be present if symptoms persist. Always discuss results with your provider.
Short name
West Nile Virus RNA (Serum/Plasma)
Frequently asked questions
When might I need this test?
What does a positive result mean?
Can I get this test at home?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy