Test Code GBACS Gamma-Amino Butyric Acid Type A (GABA-A) Receptor Antibody, Cell-Binding Assay, Serum
Specimen Required
Supplies: Sarstedt Aliquot Tube, 5 mL (T914)
Collection Container/Tube:
Preferred: Red top
Acceptable: Serum gel
Submission Container/Tube: Plastic vial
Specimen Volume: 0.3 mL
Collection Instructions: Centrifuge and aliquot serum into a plastic vial.
Secondary ID
620232Useful For
Evaluating patients with suspected autoimmune encephalitis and autoimmune epilepsy using serum specimens
Method Name
Cell-Binding Assay (CBA)
Reporting Name
GABA-A-R Ab CBA, SSpecimen Type
SerumSpecimen Minimum Volume
0.25 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | 
|---|---|---|
| Serum | Refrigerated (preferred) | 28 days | 
| Frozen | 28 days | |
| Ambient | 72 hours | 
Reject Due To
| Gross hemolysis | Reject | 
| Gross lipemia | Reject | 
| Gross icterus | Reject | 
Clinical Information
Gamma-amino butyric acid type A (GABA-A) receptor autoantibodies are highly predictive of GABA-A receptor autoimmune encephalitis. Patients who are seropositive for GABA-A receptor encephalitis have characteristic clinical-radiologic presentations including frequent seizures and multifocal lesions in the white matter. Majority of patients are treatable with immunotherapy.
Reference Values
Negative
Interpretation
Seropositivity for gamma-amino butyric acid type A receptor autoantibodies supports the clinical diagnosis of autoimmune encephalitis with neurological presentations including seizures and multifocal lesions in the white matter. A search for thymoma cancer and a trial of immunotherapy should be considered.
Day(s) Performed
Monday through Sunday
Report Available
5 to 10 daysSpecimen Retention Time
28 daysPerforming Laboratory
 Mayo Clinic Laboratories in Rochester
 Mayo Clinic Laboratories in Rochester
Test Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
86255
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value | 
|---|---|---|
| GBACS | GABA-A-R Ab CBA, S | 101874-6 | 
| Result ID | Test Result Name | Result LOINC Value | 
|---|---|---|
| 620232 | GABA-A-R Ab CBA, S | 101874-6 | 
Forms
If not ordering electronically, complete, print, and send a Neurology Specialty Testing Client Test Request (T732) with the specimen.
 
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