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Voltage-Gated Potassium Channel (VGKC) Antibody
2004890
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.
Mnemonic
VGKC AB
Methodology
Quantitative Radioimmunoassay
Performed
Tue
Reported
1-8 days
New York DOH Approval Status
This test is New York DOH approved.
Submit With Order
Specimen Required
Patient Preparation
 
Collect
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
Refrigerated.  
Unacceptable Conditions
Plasma. Grossly lipemic or icteric specimens.  
Remarks
 
Stability
After separation from cells: Ambient: Less than 72 hours; Refrigerated: 2 weeks; Frozen: 1 month (avoid repeated freeze/thaw cycles)  
Reference Interval
Negative31 pmol/L or less
Indeterminate32-87 pmol/L
Positive88 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.
Note
CPT Code(s)
83519
Components
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.
Aliases
  • VGKC Ab
  • VGKC complex
  • VGKC screen