Ordering Recommendation

Aids in the diagnosis of leucine-rich glioma inactivated 1 protein (LGI1) antibody disorders associated with limbic encephalitis, hyponatremia, and myoclonic movements. Disorders are rarely associated with tumors. Use to manage antibody-positive (LGI1) individuals following immunotherapy and/or plasmapheresis. Serum is the preferred specimen type; see Leucine-Rich, Glioma-Inactivated Protein 1 Antibody, IgG CBA-IFA with Reflex to Titer, Serum (2009456).

New York DOH Approval Status

This test is New York state approved.

Specimen Required

Patient Preparation


Specimen Preparation

Transfer 0.5 mL CSF to an ARUP standard transport tube. (Min: 0.15 mL)

Storage/Transport Temperature


Unacceptable Conditions

Contaminated, hemolyzed, or severely lipemic specimens.


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


Semi-Quantitative Cell-Based Indirect Fluorescent Antibody




1-8 days

Reference Interval

Less than 1:1

Interpretive Data

Leucine-rich, glioma-inactivated 1 protein (LGI1) IgG antibody may occur as part of the voltage-gated potassium channel (VGKC) complex antibodies.

The presence of LGI1 IgG antibody is mainly associated with limbic encephalitis, hyponatremia, and myoclonic movements. LGI1 IgG antibody is rarely associated with tumors but may occur infrequently in Morvan syndrome, neuromyotonia, and idiopathic epilepsy. The full spectrum of clinical disorders associated with the LGI1 IgG antibody continues to be defined. Results should be interpreted in correlation with the patient's clinical history and other laboratory findings.

This indirect fluorescent antibody assay utilizes LGI1 transfected cell lines for the detection and semiquantification of the LGI1 IgG antibody.

Compliance Category

Laboratory Developed Test (LDT)


If LGI1 antibody IgG is positive, then LGI1 antibody IgG titer will be added. Additional charges apply.

Hotline History


CPT Codes

86255; if reflexed, add 86256


Component Test Code* Component Chart Name LOINC
3001991 LGI1 Ab IgG CBA-IFA Screen, CSF 90830-1
* 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.


Leucine-Rich, Glioma-Inactivated Protein 1 (LGI1) Antibody, IgG by CBA-IFA With Reflex to Titer, CSF