AQUAPORINE 4 SCREENING (NMO ANTIBODIES), SERUM

Aquaporin-4 Screening (NMO Antibodies), Serum

What it is

The Aquaporin-4 Screening (NMO Antibodies), Serum test detects antibodies against the aquaporin-4 (AQP4) water channel protein. These antibodies are strongly associated with Neuromyelitis Optica Spectrum Disorder (NMOSD), an autoimmune condition that primarily affects the optic nerves and spinal cord.

Uses

This test is used to confirm or rule out NMOSD, differentiate NMOSD from multiple sclerosis (MS), and support early diagnosis of optic neuritis or transverse myelitis. It also helps in guiding treatment decisions and monitoring patients with suspected or confirmed autoimmune demyelinating disorders.

Symptoms That May Lead to the Test

Doctors may recommend this test if you have symptoms such as sudden vision loss, eye pain, weakness or numbness in the limbs, paralysis, recurrent optic neuritis, unexplained spinal cord inflammation, or severe attacks of demyelination not typical of MS.

Abnormal Results

Positive AQP4 Antibodies: Strongly suggests Neuromyelitis Optica Spectrum Disorder (NMOSD) and helps distinguish it from multiple sclerosis or other autoimmune conditions.

Negative AQP4 Antibodies: Does not rule out NMOSD completely. Some patients may have MOG (myelin oligodendrocyte glycoprotein) antibodies instead, requiring additional testing.

Risks

The test requires a standard blood sample and carries minimal risks. Mild pain, bruising, or bleeding at the puncture site may occur. Rarely, dizziness or infection can develop.