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HelpTest Code LAB1232165 Neuromyelitis Optica (NMO)/Aquaporin-4-IgG Fluorescence-Activated Cell Sorting (FACS) Assay, Spinal Fluid
Useful For
Diagnosis of a neuromyelitis optica spectrum disorder (NMOSD)
Diagnosis of autoimmune AQP4 channelopathy
Distinguishing NMOSD from multiple sclerosis early in the course of disease
Reflex Tests
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| NMOTC | NMO/AQP4 FACS Titer, CSF | No | No |
Testing Algorithm
When the results of this assay require further evaluation, NMOTC / Neuromyelitis Optica (NMO)/Aquaporin-4-IgG Fluorescence-Activated Cell Sorting (FACS) Assay Titer, Spinal Fluid will be performed at an additional charge.
Reporting Name
NMO/AQP4 FACS, CSFSpecimen Type
CSFOrdering Guidance
Necessary Information
Include relevant clinical information, name, phone number, mailing address, and e-mail address (if applicable) of ordering physician.
Specimen Required
Collection Container/Tube: Sterile vial
Specimen Volume: 3 mL
Specimen Minimum Volume
2 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| CSF | Refrigerated (preferred) | 28 days | |
| Frozen | 28 days | ||
| Ambient | 72 hours |
Reject Due To
| Gross hemolysis | OK |
| Gross lipemia | OK |
| Gross icterus | OK |
Reference Values
Negative
Supportive Data
Recent AQP4 FACS analysis of paired cerebrospinal fluid (CSF) and serum samples from 66 patients submitted for AQP4-IgG testing reveals a slightly better detection rate in serum (n=59) compared with CSF (n=55). All 7 patients who tested negative in serum also tested negative in CSF.
AQP4 FACS analysis was done for CSF samples from 26 random patients with a diagnosis of NMO. All samples except 1 were tested with our validated AQP4 cell-binding assay (CBA). A total of 18 samples (69.23%) were positive by FACS, while only 14 samples (56%) were positive by CBA. All 8 samples that were negative by FACS also tested negative by CBA.
To measure the specificity, AQP4 FACS analysis was done for CSF of 27 patients with the diagnosis of normal pressure hydrocephalus. None of the samples were positive by this assay (specificity=100%).
Day(s) Performed
Monday, Tuesday, Thursday
Report Available
5 to 8 daysSpecimen Retention Time
28 daysPerforming Laboratory
Mayo Clinic Laboratories in Rochester
CPT Code Information
86053
86053-titer (if appropriate)
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| NMOFC | NMO/AQP4 FACS, CSF | 46718-3 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 38325 | NMO/AQP4-IgG FACS, CSF | 46718-3 |