NMO (aquaporin-4) antibody test
Quick answer: This test looks for antibodies against aquaporin-4, a water channel protein in the brain, spinal cord and optic nerves. Doctors usually order it when they suspect neuromyelitis optica spectrum disorder, for example after optic neuritis or spinal cord inflammation.
- SampleBlood or CSF (spinal fluid)
- TakesAbout 5 minutes for blood; 20 to 30 minutes for a lumbar puncture
- Before the testNo special preparation is usually needed for the blood test; a CSF sample is collected by a doctor through a lumbar puncture.
How the test is done
- 1For blood, a nurse draws a tube from a vein in your arm
- 2For spinal fluid, you lie curled on your side
- 3A doctor numbs your lower back and collects fluid with a thin needle
- 4The lab tests the sample for aquaporin-4 antibodies, often by a cell-based assay
What your results can mean
Reading your report
A positive result does not by itself confirm a disease, because some healthy people test positive; your doctor reads it with your symptoms and other tests.
If the result is outside the usual range
A positive result strongly supports neuromyelitis optica spectrum disorder, which can affect the optic nerves and spinal cord. A negative result does not fully rule it out, and doctors may test for MOG antibodies too.
Who usually has this test
People with optic neuritis, inflammation of the spinal cord, or symptoms that look like multiple sclerosis but have unusual features.
Risks and aftercare
After blood tests there is nothing special; after a lumbar puncture you may have a headache and are advised to rest.
Names and options
Also called: NMO, AQP4 antibody, NMO-IgG, neuromyelitis optica antibody
Options
- Serum
- CSF
Listed by the hospital as
- NMO (NEUROMYELITIS OPTICA), CSF
- NMO (NEUROMYELITIS OPTICA), SERUM
Questions about this test
How is NMO different from multiple sclerosis?
Both can affect the optic nerves and spinal cord, but NMO is driven by aquaporin-4 antibodies and needs different treatment. Some MS treatments can make NMO worse, so the test matters.
Is the blood test or spinal fluid test better for aquaporin-4?
Blood testing is usually preferred for this antibody. Spinal fluid is sometimes tested when the blood result is unclear.
Can NMO affect pregnancy?
Attacks can be more likely after giving birth. Women with NMO are advised to plan pregnancy with their neurologist.
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.