Ordering Recommendation

Aid in diagnosis of limbic encephalitis. May be used in monitoring treatment response in individuals who are antibody positive. The presence of GABA-BR antibodies may be associated with seizures; GABA-BR encephalitis may be paraneoplastic as about 50% of cases are associated with small cell lung cancer.

Mnemonic

GABA-B CSF

Methodology

Semi-Quantitative Indirect Fluorescent Antibody

Performed

Wed

Reported

1-8 days

New York DOH Approval Status

This test is New York DOH approved.

Specimen Required

Patient Preparation
Collect

CSF.

Specimen Preparation

Transfer 0.5 mL CSF to an ARUP Standard Transport Tube. (Min: 0.15 mL)

Storage/Transport Temperature

Refrigerated.

Unacceptable Conditions

Hemolyzed, contaminated, or severely lipemic specimens.

Remarks
Stability

Ambient: 48 hours; Refrigerated: 2 weeks; Frozen: 1 month

Reference Interval

Less than 1:1

Interpretive Data

Gamma-amino butyric acid receptor, type B (GABA-BR) antibody is found in a subset of patients with autoimmune limbic encephalitis and may occur with or without associated tumor. Decreasing antibody levels may be associated with therapeutic response; therefore, clinical correlation must be strongly considered. A negative test result does not rule out a diagnosis of autoimmune encephalitis.

This indirect fluorescent antibody assay utilizes GABA-BR transfected cell lines for the detection and semi-quantification of GABA-BR IgG antibody.

This test was developed and its performance characteristics determined by ARUP Laboratories. It has not been cleared or approved by the US Food and Drug Administration. This test was performed in a CLIA certified laboratory and is intended for clinical purposes.

Compliance Category

Laboratory Developed Test (LDT)

Note

If Gamma Aminobutyric Acid Receptor, Type B (GABA-BR) Antibody, IgG by IFA with Reflex to Titer, CSF is positive, then a Gamma Aminobutyric Acid Receptor, Type B (GABA-BR) Antibody Titer, IgG, CSF is performed. Additional charges apply.

Hotline History

N/A

CPT Codes

86255; if reflexed, add 86256

Components

Component Test Code* Component Chart Name LOINC
3001268 GABA-B Receptor Ab IgG Screen, CSF 82984-6
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.

Aliases

  • GABA
  • GABA Receptor
  • GABA Reflex
  • GABA Titer
  • GABA-B
Gamma Aminobutyric Acid Receptor, Type B (GABA-BR) Antibody, IgG by IFA with Reflex to Titer, CSF