West Nile virus antibody test
Quick answer: This blood test measures antibodies against West Nile virus, a mosquito-borne virus. Doctors may order it when West Nile infection is suspected, for example with fever and signs of brain or nerve involvement.
- SampleBlood
- TakesAbout 5 minutes
- Before the testNo special preparation is usually needed.
How the test is done
- 1You sit and your sleeve is rolled up
- 2A vein on your arm is cleaned
- 3A needle collects a tube of blood
- 4The lab tests for West Nile IgM and IgG antibodies
What your results can mean
Reading your report
A positive IgM usually suggests a recent or current infection and a positive IgG a past infection or immunity, but your doctor will read the result alongside your symptoms. Antibodies to related viruses such as dengue can cross-react.
If the result is outside the usual range
A positive IgM can point to a recent West Nile infection, which sometimes affects the brain or nerves. Antibodies from dengue or Japanese encephalitis can cross-react, so confirmation tests may be needed.
Who usually has this test
People with fever and headache, neck stiffness, confusion or weakness after mosquito exposure.
Risks and aftercare
The blood draw is quick and needs no aftercare; a bruise may appear.
Names and options
Also called: West Nile IgM, West Nile IgG, WNV antibody
Options
- IgG
- IgM
Listed by the hospital as
- WEST NILE IGG
- WEST NILE IGM
Questions about this test
Is West Nile virus found in India?
Yes, West Nile virus has been reported in parts of India, including the south. Most infections cause mild or no symptoms.
Why can dengue affect a West Nile result?
These viruses belong to the same family, so antibodies to one can react on tests for another. A specialist lab may run extra tests to sort this out.
Can West Nile infection be serious?
A small number of people develop brain or nerve inflammation, especially older adults. Most people recover with supportive care.
Related tests
Tamara Hospital & IVF Centre, Rajajinagar
34/3, 10th Cross Road, opp. Vardhaka Sardar Patel School, 1st N Block, 2nd Stage, Rajajinagar, Bengaluru 560010
The hospital is open 24 hours. Call before you come to check the timing for your scan or sample collection.
Get directions ↗IVF Pulse fertility care at Tamara Hospital →
Reception
Waiting area
IVF lab
This page explains each test in general terms so you know what to expect. It is not medical advice: your doctor decides which tests you need and what your results mean. Reference ranges differ between laboratories. Updated 4 November 2026.