Japanese encephalitis virus (JEV) RNA PCR
Quick answer: This test looks for the genetic material of Japanese encephalitis virus, a mosquito-borne virus that can infect the brain. It may be ordered for fever with confusion, seizures or other signs of brain infection in areas where the virus occurs.
- SampleFluid (CSF) or blood
- TakesA few minutes for blood; about 20 to 30 minutes for a lumbar puncture
- Before the testNo special preparation is usually needed for blood; CSF is collected by a doctor.
How the test is done
- 1A sample of spinal fluid or blood is taken
- 2Spinal fluid is collected by lumbar puncture
- 3The lab extracts RNA from the sample
- 4A PCR test looks for Japanese encephalitis virus genetic material
What your results can mean
Reading your report
The virus is often present only briefly, so a negative PCR does not rule out infection and antibody tests may be added.
If the result is outside the usual range
A positive result can confirm Japanese encephalitis. A negative result does not rule it out, as the virus has often cleared by the time symptoms appear, so antibody tests are also used.
Who usually has this test
People with fever and brain symptoms, such as confusion or seizures, especially children in areas where the virus spreads.
Risks and aftercare
Aftercare depends on the sample; a lumbar puncture can cause a headache.
Names and options
Also called: JE PCR, Japanese encephalitis test
Listed by the hospital as
- JEV RNA PCR
Questions about this test
Is Japanese encephalitis found in Karnataka?
Yes, cases are reported in parts of India including Karnataka, mostly in rural areas with rice fields and pigs. It spreads through mosquito bites.
Can Japanese encephalitis be prevented?
A vaccine is available and is part of India's immunisation programme in affected districts. Avoiding mosquito bites also helps.
Why are antibody tests used as well?
The virus is often cleared from blood and spinal fluid early. IgM antibody tests on spinal fluid are commonly used to confirm infection.
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.
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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.