Voltage-Gated Potassium Channel (VGKC) Antibody
Ordering Recommendation
Screening test for Voltage-Gated Potassium Channel (VGKC) antibody receptor complex-associated autoantibodies. Assay does not identify Contactin Associated Protein 2 (CASPR2) Antibody or Leucine-rich Glioma Inactivated 1 Protein (LGI1) antibodies individually. Use to manage antibody-positive (VGKC, LGI1, or CASPR2) individual following immunotherapy and/or plasmapheresis.
Quantitative Radioimmunoassay
1-8 days  
New York DOH Approval Status
This test is New York DOH approved.
Submit With Order
Specimen Required
Patient Preparation
Plain red or serum separator tube.  
Specimen Preparation
Separate serum from cells within 1 hour. Transfer 4 mL serum to an ARUP Standard Transport Tube. (Min: 0.5 mL)  
Storage/Transport Temperature
Unacceptable Conditions
Plasma. Grossly lipemic or icteric specimens.  
After separation from cells: Ambient: Less than 72 hours; Refrigerated: 2 weeks; Frozen: 1 month (avoid repeated freeze/thaw cycles)  
Reference Interval
Effective April 18, 2011
Negative 31 pmol/L or less
Indeterminate 32-​87 pmol/L
Positive 88 pmol/L or greater
Interpretive Data
Voltage-Gated Potassium Channel (VGKC) antibodies are associated with neuromuscular weakness as found in neuromyotonia (also known as Issacs syndrome) and Morvan syndrome. VGKC antibodies are also associated with paraneoplastic neurological syndromes and limbic encephalitis; however, VGKC antibody-associated limbic encephalitis may be associated with antibodies to leucine-rich, glioma-inactivated 1 protein (Lgi1) or contactin-associated protein-2 (Caspr-2) instead of potassium channel antigens.The clinical significance of this test can only be determined in conjunction with the patient's clinical history and related laboratory testing.

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.
CPT Code(s)
Component Test Code*Component Chart NameLOINC
2004890Voltage-Gated Potassium Channel (VGKC)Ab41871-5
* 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.
  • VGKC Ab
  • VGKC complex
  • VGKC screen