Leucine-Rich, Glioma-Inactivated Protein 1 Antibody, IgG and Contactin-Associated Protein-2 Antibody, IgG with Reflex to Titers
Ordering Recommendation
Aids in diagnosis of
•Leucine-rich Glioma Inactivated 1 Protein (LGI1) Antibody disorders associated with limbic encephalitis, hyponatremia, myoclonic movements. Disorders are rarely associated with tumors.
•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.
Semi-Quantitative Indirect Fluorescent Antibody
1-8 days  
New York DOH Approval Status
This test is New York DOH approved.
Submit With Order
Specimen Required
Patient Preparation
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
Unacceptable Conditions
CSF or plasma. Contaminated, hemolyzed, or severely lipemic specimens.  
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
2009456Leucine-​Rich, Glioma-​Inactivated Protein 1 Antibody, IgG with Reflex to Titer Less than 1:10
2009452Contactin-​Associated Protein-​2 Antibody, IgG with Reflex to Titer Less than 1:10
Interpretive Data

Compliance Statement D: This test was developed and its performance characteristics determined by ARUP Laboratories. The U.S. Food and Drug Administration has not approved or cleared this test; however, FDA clearance or approval is not currently required for clinical use. The results are not intended to be used as the sole means for clinical diagnosis or patient management decisions.
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.
CPT Code(s)
86255 x2; if reflexed add 86256 per titer
Component Test Code*Component Chart NameLOINC
2009453CASPR2 Ab IgG Screen by IFA 
2009457LGI1 Ab IgG Screen by IFA 
* 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.