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Viral IgM Antibody to West Nile Virus (Serum/Plasma)

Published: August 9, 2026Updated: August 16, 2026

This test detects antibodies in your blood that your immune system produces in response to the West Nile virus. It helps identify if you’ve recently been exposed to the virus.

Quick summary

["This test checks for recent West Nile virus infection by detecting early immune system responses."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
55402-2
Short code
WNV IgG+IgM Pnl Ser
Synonyms
WNV IgG+IgM Pnl Ser
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
82784
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

Why This Test Matters

West Nile virus is spread by mosquitoes and can affect the nervous system, causing symptoms like fever, headache, or neurological issues. Detecting early exposure helps doctors monitor your health and plan appropriate care.

What to Expect During Testing

A blood sample is taken from a vein in your arm. You may feel a slight pinch, but it’s usually over quickly. The test involves sending your serum or plasma to a lab for analysis.

What the Results Mean

Positive results indicate recent West Nile virus exposure, typically within the first few weeks. Negative results mean no detectable antibodies at this time, but exposure could still have occurred without symptoms.

Common Symptoms of West Nile Virus

Symptoms may include fever, headache, body aches, nausea, or neurological issues like muscle weakness or confusion. Not everyone gets sick, but early detection can help guide treatment decisions.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

West Nile IgM Antibody

Frequently asked questions

How long does it take to get results from this test?
Results are usually available within 24 to 72 hours, depending on lab processing times. Follow-up with your healthcare provider for interpretation.
Can I get West Nile virus from this test?
No, this test only detects antibodies—it does not expose you to the virus. Blood samples are handled safely and destroyed after testing.
What if my results are positive but I don’t feel sick?
Even without symptoms, a positive result means your body has mounted an immune response. Your doctor may recommend further evaluation or monitoring based on your health history and exposure risk.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

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.

Medical Disclaimer

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