-1739993209.png){kind=logo}
Home
HelpTest Code GD65C Glutamic Acid Decarboxylase (GAD65) Antibody Assay, Spinal Fluid
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Specimen Type
CSFOrdering Guidance
This test should not be requested in patients who have recently received radioisotopes, therapeutically or diagnostically, because of potential assay interference. The specific waiting period before specimen collection will depend on the isotope administered, the dose given, and the clearance rate in the individual patient. Specimens will be screened for radioactivity prior to analysis. Radioactive specimens received in the laboratory will be held one week and assayed if sufficiently decayed or canceled if radioactivity remains.
Specimen Required
Container/Tube: Sterile vial
Specimen Volume: 1.5 mL
Collection Instructions: Submit specimen from collection vial 2.
Specimen Minimum Volume
1 mL
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| CSF | Refrigerated (preferred) | 28 days |
| Frozen | 28 days | |
| Ambient | 72 hours |
Reference Values
≤0.02 nmol/L
Reference values apply to all ages.
Day(s) Performed
Monday through Sunday
CPT Code Information
86341
Clinical Information
Glutamic acid decarboxylase (GAD) is a neuronal enzyme involved in the synthesis of the neurotransmitter gamma-aminobutyric acid (GABA). Serum antibodies directed against the 65-kDa isoform of GAD (GAD65) are detected in heightened frequency in a variety of autoimmune neurologic disorders, including autoimmune encephalitis, stiff-person (Moersch-Woltman) syndrome, autoimmune ataxia, and autoimmune epilepsy.
Report Available
3 to 6 daysReject Due To
| Gross hemolysis | Reject |
| Gross lipemia | Reject |
| Gross icterus | Reject |
Method Name
Radioimmunoassay (RIA)
Forms
If not ordering electronically, complete, print, and send a Neurology Specialty Testing Client Test Request (T732) with the specimen.