Ordering Recommendation

Aid in 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) individual following immunotherapy and/or plasmapheresis. Serum is the preferred specimen type; see Leucine-Rich, Glioma-Inactivated Protein 1 Antibody, IgG with Reflex to Titer (2009456).

Mnemonic
LGI1IGGCSF
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

Contaminated, hemolyzed, or severely lipemic specimens.

Remarks
Stability

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

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 leucine-rich, glioma-inactivated 1 protein (LGI1) transfected cell lines for the detection and semi-quantification of the LGI1 IgG antibody.

Compliance Category

Laboratory Developed Test (LDT)

Note

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

Hotline History
N/A
CPT Codes

86255; if reflexed, add 86256

Components
Component Test Code* Component Chart Name LOINC
3001991 LGI1 Ab IgG Screen by IFA, 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.
Aliases
Leucine-Rich, Glioma-Inactivated Protein 1 Antibody, IgG with Reflex to Titer, CSF