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.
Aid in diagnosis of contactin associated protein 2 (CASPR2) antibody disorders associated with acquired neuromyotonia, limbic encephalitis, painful neuropathy, and Morvan syndrome.
Use to manage antibody-positive (LGI1 or CASPR2) individual following immunotherapy and/or plasmapheresis

Mnemonic
LGI1CASPR2
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

Serum separator tube.

Specimen Preparation

Separate serum from cells within 2 hours of collection. Transfer 1 mL serum to an ARUP Standard Transport Tube. (Min: 0.2 mL)

Storage/Transport Temperature

Refrigerated.

Unacceptable Conditions

CSF or plasma. Contaminated, hemolyzed, or severely lipemic specimens.

Remarks
Stability

After separation from cells: Ambient: 48 hours; Refrigerated: 2 weeks; Frozen: 1 year (avoid repeated freeze/thaw cycles)

Reference Interval
Test Number
Components
Reference Interval
2009456 Leucine-Rich, Glioma-Inactivated Protein 1 Antibody, IgG with Reflex to Titer, Serum Less than 1:10
2009452 Contactin-Associated Protein-2 Antibody, IgG with Reflex to Titer, Serum Less than 1:10

Interpretive Data



Compliance Category

Laboratory Developed Test (LDT)

Note

If LGI1 antibody IgG is positive, then LGI1 antibody IgG titer will be added. If CASPR2 antibody IgG is positive, then CASPR2 antibody IgG titer will be added. Additional charges apply.

Hotline History
N/A
CPT Codes

86255 x2; if reflexed add 86256 per titer

Components
Component Test Code* Component Chart Name LOINC
2009453 CASPR2 Ab IgG Screen by IFA, Serum 82979-6
2009457 LGI1 Ab IgG Screen by IFA, Serum 82978-8
* 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 and Contactin-Associated Protein-2 Antibody, IgG with Reflex to Titers, Serum