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Test Code GBACS Gamma-Amino Butyric Acid Type A (GABA-A) Receptor Antibody by Cell Binding Assay, Serum


Specimen Required


Supplies: Sarstedt Aliquot Tube, 5 mL (T914)

Collection Container/Tube:

Preferred: Red top

Acceptable: SST

Submission Container/Tube: Plastic vial

Specimen Volume: 0.30 mL

Collection Instructions: Centrifuge and aliquot serum into a plastic vial.


Useful For

Evaluating patients with suspected autoimmune encephalitis and autoimmune epilepsy.

Method Name

Cell Binding Assay (CBA)

Reporting Name

GABA-A-R Ab CBA, S

Specimen Type

Serum

Specimen Minimum Volume

0.25 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum Refrigerated (preferred) 28 days
  Frozen  28 days
  Ambient  72 hours

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.

Clinical Reference

1. O’Connor K, Waters P, Komorowski L, et al. GABAA receptor autoimmunity A multicenter experience. Neurol Neuroimmunol Neuroinflamm 2019;6(3):e552. doi:10.1212/NXI.0000000000000552

2. Spatola M, Petit-Pedrol M, Simabukuro MM, et al. Investigations in GABAA receptor antibody-associated encephalitis. Neurology. 2017; 88(11): 1012–1020. doi:10.1212/WNL.0000000000003713

3. Waters P, Irani S. GABA-A receptor antibodies and their clinical associations. Neurology 2017; 88:1010–1011

4. Petit-Pedrol M, Armangue T, Peng X, et al. Encephalitis with refractory seizures, status epilepticus, and antibodies to the GABAA receptor: a case series, characterization of the antigen, and analysis of the effects of antibodies. Lancet Neurol 2014;13(3):276–286

Day(s) Performed

Monday through Sunday

Report Available

5 to 10 days

Performing Laboratory

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