Autoimmune Stiff-Person Disorders, Serum
Also known as: AISPSS
Use
The test is used to evaluate stiffness, spasms, hyperekplexia, limb rigidity, myoclonus, or limb dystonia, whether or not there is encephalopathy. It is recommended in cases of immune-mediated movement disorder presentations. Testing both serum and CSF is advised to increase diagnostic yield. The presence of antibodies such as Amphiphysin and GAD can indicate autoimmune neurologic conditions, often linked with cancer.
Special Instructions
If DPPX antibody IgG by IFA is positive, then titer will be added with additional charges. Testing in both serum and CSF is recommended to maximize diagnostic yield. Ensure specimens are separated from cells as soon as possible, ideally within 2 hours of collection.
Limitations
A negative result does not rule out a diagnosis of autoimmune neurologic disease. Results should be interpreted within the context of clinical history and other laboratory findings. Semi-quantitative methods may have variations in sensitivity. Amphiphysin antibody is present in about 5% of stiff-person syndrome cases and is associated with specific cancer types.
New York Approved
Methodology
Immunoassay (ELISA)
Biomarkers
LOINC Codes
- 94385-2
- 56540-8
- 94676-4
Result Turnaround Time
3-10 days
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
3 mL
Minimum Volume
0.5 mL/aliquot
Container
Serum separator tube (SST)
Collection Instructions
Separate from cells ASAP or within 2 hours of collection. Transfer three 1 mL serum aliquots to ARUP standard transport tubes.
Causes for Rejection
Amniotic fluid, ocular fluid, peritoneal fluid, synovial fluid, CSF, or plasma. Contaminated, hemolyzed, icteric, or lipemic specimens.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 24 hours |
| Refrigerated | 1 week |
| Frozen | 30 days |