Ordering Recommendation

Detect antibodies to voltage-gated potassium channel (VGKC) antibody receptor complex-associated, leucine-rich glioma inactivated 1 protein (LGI1) and contactin associated protein 2 (CASPR2). Antibodies are associated with acquired neuromyotonia, limbic encephalitis, painful neuropathy, Morvan syndrome, and rare tumors (eg, thymoma, small cell lung cancer). Serum is the preferred specimen type; see Voltage-Gated Potassium Channel (VGKC) Antibody with Reflex to LGI1 and CASPR2 Screen and Titer, Serum (2009463).




Quantitative Radioimmunoassay/Semi-Quantitative Indirect Fluorescent Antibody




1-8 days

New York DOH Approval Status

This test is New York DOH approved.

Specimen Required

Patient Preparation


Specimen Preparation

Transfer 4 mL CSF to an ARUP Standard Transport Tube. (Min: 1.0 mL)

Storage/Transport Temperature


Unacceptable Conditions

Plasma. Grossly lipemic or icteric specimens.


After separation from cells: Ambient: 48 hours; Refrigerated: 2 weeks; Frozen: 1 month

Reference Interval

Test Number
Reference Interval
3001387 Voltage-Gated Potassium Channel (VGKC) Antibody, CSF
Negative 0.0-1.1 pmol/L
Positive 1.2 pmol/L or greater

3001992 Leucine-Rich, Glioma-Inactivated Protein 1 Antibody, IgG with Reflex to Titer, CSF Less than 1:1
3001986 Contactin-Associated Protein-2 Antibody, IgG with Reflex to Titer, CSF Less than 1:1

Interpretive Data

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)


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


CPT Codes

83519; 86255 x2; if reflexed add 86256 per titer


Component Test Code* Component Chart Name LOINC
3001388 Voltage-Gated Potassium Channel Ab, CSF 68913-3
3001987 CASPR2 Ab IgG Screen by IFA, CSF 90820-2
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.


Voltage-Gated Potassium Channel (VGKC) Complex Antibody Panel with Reflex to Titer, CSF