Amphiphysin Antibody Titer Assay, Spinal Fluid
Use
This test is used to evaluate patients with recent onset of subacute neurological disorders where a paraneoplastic basis might be suspected. It is particularly useful when the patient has a history of cancer, especially lung or breast cancer. The test detects antineuronal autoantibodies specific for amphiphysin, a 128-kDa synaptic vesicle-associated protein, which are markers of autoimmune encephalomyeloneuritis, sensory neuronopathy, and neuromyopathic disorders linked to small-cell lung carcinoma or breast carcinoma.
Special Instructions
This test is only orderable as a reflex, often included in evaluations for potential paraneoplastic syndromes such as dementia, encephalopathy, epilepsy, movement disorders, myelopathy, and stiff-person spectrum disorders. A positive result implies antineuronal autoimmunity often related to cancers like breast or small-cell lung carcinoma.
Limitations
Nonorgan-specific autoantibodies at high titers can preclude identification of amphiphysin IgG via indirect immunofluorescence. In such cases, a Western blot assay should be considered. Additional confirmatory testing may be needed for comprehensive diagnosis, particularly in complex clinical scenarios.
New York Approved
Methodology
Immunoassay (Indirect Immunofluorescence Assay (IFA))
Biomarkers
LOINC Codes
- 94354-8
- 94354-8
Result Turnaround Time
6-8 days
Related Documents
For more information, please review the documents below
Specimen
Cerebrospinal Fluid
Volume
4 mL
Minimum Volume
2 mL
Container
Sterile vial
Collection Instructions
CSF should be refrigerated (preferred), kept ambient for up to 72 hours, or frozen for longer stability.
Causes for Rejection
Gross hemolysis, Gross lipemia, Gross icterus
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 72 hours |
| Refrigerated | 28 days |
| Frozen | 28 days |