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25597 Neuromyelitis Optica (NMO)/Aquaporin-4-IgG Fluorescence-Activated Cell Sorting (FACS) Assay, Serum

Neuromyelitis Optica (NMO)/Aquaporin-4-IgG Fluorescence-Activated Cell Sorting (FACS) Assay, Serum
Test Code: NMOFSSO
Synonyms/Keywords
AQP, AQP4, Aquaporin, Devic's Antibody, NMO (Neruomyelitis Optica), NMO-IgG, Optic Neuritis Antibody, Transverse Myelitis Antibody, Vision Loss Antibody33
Test Components
When the results of this assay require further evaluation, NMOTS/Neuromyelitis Optica (NMO)/Auaporin-4-IgG Fluorescence-Activated Cell Sorting (FACS) Titer Assay, Serum will be performed at an additional charge.
Useful For

Diagnosis of neuromyelitis optica spectrum disorder (NMOSD)

Diagnosis of autoimmune AQP4 channelopathy

Diagnosis of neuromyelitis optica (NMO)

Distinguishing NMOSD from multiple sclerosis early in the course of disease

Specimen Requirements
Fasting Required Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)
Pediatric Minimum Volume
(no repeat)
​No ​Serum ​Red Top Tube (RTT) ​Serum Separator Tube (SST) ​3.0 mL ​2.0 mL
Specimen Stability Information
Specimen Type Temperature Time
​Serum ​ ​ ​Refrigerated (preferred) ​28 days
​Ambient ​72 hours
​Frozen ​28 days
Interference
​AQP4-IgG antibodies may drop below detectable levels in setting of therapies for acute attack (IV methylprednisolone or plasmapheresis) or attack prevention (immunosuppressants).
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
​Mayo Clinic Laboratories ​Monday, Tuesday, Thursday ​5-8 days Flow Cytometry
Reference Lab
Test Information

Neuromyelitis optica (NMO), sometimes called Devic disease or opticospinal multiple sclerosis [MS]) is a severe, relapsing, autoimmune, inflammatory and demyelinating central nervous system disease that predominantly affects optic nerves and spinal cord. The disorder is now recognized as a spectrum of autoimmunity (termed NMO spectrum disorders [NMOSD]) targeting the astrocytic water channel aquaporin-4 (AQP4). Brain lesions are observed in >60% of patients with NMOSD and approximately 10% will be MS-like. Children tend to have greater brain involvement than adults and brain lesions are more symptomatic than is typical for adult patients. Extensive cerebral white matter signal abnormalities are sometimes encountered, most commonly in children, and are sometimes associated with encephalopathy. Circumventricular organs (CVO; eg, area postrema) are preferentially involved. Symptoms and signs attributable to area postrema involvement include intractable hiccups, nausea and vomiting, and these may occur in isolation, herald the onset of NMO or occur in association with the more classical optic neuritis or Longitudinally Extensive Transverse Myelitis (LETM). Magnetic resonance imaging typically reveals large inflammatory spinal cord lesions involving 3 or more vertebral segments. During acute attacks, the cerebrospinal fluid contains inflammatory cells, but usually lacks evidence of intrathecal IgG synthesis. The clinical course is characterized by relapses of optic neuritis or transverse myelitis, or both. Many patients with NMOSD are misdiagnosed as having MS. Importantly, the prognosis and optimal treatments for the 2 diseases differ. NMOSD typically has a worse natural history than MS, with frequent and early relapses. NMOSD attacks are often severe resulting in a rapid accumulation of disability (blindness and paraplegia). More effective treatments combined with earlier and more accurate diagnosis has led to improved outcomes. Currently, in the AQP4-IgG era, 5 years after onset, approximately 30% of NMO patients will require a cane to walk and 10% will be wheelchair bound. Treatments for NMOSD include corticosteroids and plasmapheresis for acute attacks and mycophenolate mofetil, azathioprine, and rituximab for relapse prevention. Beta-interferon, a treatment promoted for MS, exacerbates NMOSD. Therefore, early diagnosis and initiation of NMO-appropriate immunosuppressant treatment is important to optimize the clinical outcome by preventing further attacks. Skeletal muscle abnormalities with hyperCKemia have been reported in a few NMOSD patients. Recent reports indicate focal retinal vascular attenuation, inner nuclear layer thickening and microcystic edema in some NMO patients. The sensitivity and specificity of Fluorescence-Activated Cell Sorting (FACS) assay for NMO is >80% and >99%, respectively.

Detection of NMO/APQ4-IgG allows distinction of NMOSD from MS and is indicative of a relapsing disease, mandating initiation of immunosuppression, even after the first attack, thereby reducing attack frequency and disability in the future.

Reference Range Information
Negative
Interpretation
​A positive value is consistent with a neuromyelitis optica spectrum disorder (NMOSD) and justifies initiation of appropriate immunosuppressive therapy at the earliest possible time. This allows early initiation and maintenance of optimal therapy. Recommend follow-up in 3 to 6 months if NMOSD is suspected.
 
This autoantibody is not found in healthy subjects.
Outreach CPTs
CPT Modifier
(if needed)
Quantity Description Comments
​86255 ​1 ​Fluorescent noninfectious agent antibody; screen each, antibody
​86256 ​1 ​Fluorescent noninfectious agent antibody; titer, each antibody ​If needed
Synonyms/Keywords
AQP, AQP4, Aquaporin, Devic's Antibody, NMO (Neruomyelitis Optica), NMO-IgG, Optic Neuritis Antibody, Transverse Myelitis Antibody, Vision Loss Antibody33
Test Components
When the results of this assay require further evaluation, NMOTS/Neuromyelitis Optica (NMO)/Auaporin-4-IgG Fluorescence-Activated Cell Sorting (FACS) Titer Assay, Serum will be performed at an additional charge.
Ordering Applications
Ordering Application Description
If the ordering application you are looking for is not listed, contact your local laboratory for assistance.
Specimen Requirements
Fasting Required Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)
Pediatric Minimum Volume
(no repeat)
​No ​Serum ​Red Top Tube (RTT) ​Serum Separator Tube (SST) ​3.0 mL ​2.0 mL
Specimen Stability Information
Specimen Type Temperature Time
​Serum ​ ​ ​Refrigerated (preferred) ​28 days
​Ambient ​72 hours
​Frozen ​28 days
Interference
​AQP4-IgG antibodies may drop below detectable levels in setting of therapies for acute attack (IV methylprednisolone or plasmapheresis) or attack prevention (immunosuppressants).
Useful For

Diagnosis of neuromyelitis optica spectrum disorder (NMOSD)

Diagnosis of autoimmune AQP4 channelopathy

Diagnosis of neuromyelitis optica (NMO)

Distinguishing NMOSD from multiple sclerosis early in the course of disease

Test Components
When the results of this assay require further evaluation, NMOTS/Neuromyelitis Optica (NMO)/Auaporin-4-IgG Fluorescence-Activated Cell Sorting (FACS) Titer Assay, Serum will be performed at an additional charge.
Reference Range Information
Negative
Interpretation
​A positive value is consistent with a neuromyelitis optica spectrum disorder (NMOSD) and justifies initiation of appropriate immunosuppressive therapy at the earliest possible time. This allows early initiation and maintenance of optimal therapy. Recommend follow-up in 3 to 6 months if NMOSD is suspected.
 
This autoantibody is not found in healthy subjects.
For more information visit:
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
​Mayo Clinic Laboratories ​Monday, Tuesday, Thursday ​5-8 days Flow Cytometry
Reference Lab
For billing questions, see Contacts
Outreach CPTs
CPT Modifier
(if needed)
Quantity Description Comments
​86255 ​1 ​Fluorescent noninfectious agent antibody; screen each, antibody
​86256 ​1 ​Fluorescent noninfectious agent antibody; titer, each antibody ​If needed
For most current information refer to the Marshfield Laboratory online reference manual.