N-methyl-D-Aspartate Receptor (NMDAR) Antibody, IgG by CBA-IFA, CSF With Reflex to Titer
Also known as: NMDA G CSF
Use
This test is utilized to confirm the diagnosis of anti-NMDA receptor encephalitis, an autoimmune condition that primarily affects the brain. It is significant for its role in identifying antibodies associated with this condition, which can cause psychiatric symptoms, seizures, and autonomic instability. The test may also be employed to monitor treatment response in individuals who test positive for these antibodies. The presence of NMDA receptor antibodies is observed in some patients with limbic encephalitis and, potentially, without related tumors. The correlation with decreasing antibody levels may reflect a positive therapeutic response.
Special Instructions
If the NMDA CSF antibody IgG is positive, an additional titer is performed, incurring an extra charge. This test is approved for use in the state of New York and performed exclusively on CSF specimens, maximizing efficiency for detecting and semi-quantifying NMDA receptor IgG antibodies.
Limitations
A negative test result does not rule out a diagnosis of autoimmune limbic encephalitis, indicating that the results should be considered in conjunction with clinical history and other laboratory findings. The test results may also occasionally display positive findings in patients with non-autoimmune phenotypes, which requires cautious interpretation.
New York Approved
Methodology
Cell-based / Cytometry (Other)
Biomarkers
LOINC Codes
- 80220-7
Result Turnaround Time
1-3 days
Related Documents
For more information, please review the documents below
Specimen
Cerebrospinal Fluid
Volume
0.5 mL
Minimum Volume
0.15 mL
Container
ARUP standard transport tube
Storage Instructions
Refrigerated
Causes for Rejection
Contaminated, hemolyzed, or severely lipemic specimens
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 48 hours |
| Refrigerated | 2 weeks |
| Frozen | 1 year (avoid repeated freeze/thaw cycles) |