Voltage-Gated Potassium Channel (VGKC) Antibody with Reflex to LGI1 and CASPR2 Screen and Titer, Serum
Screening test for voltage-gated potassium channel (VGKC) antibody receptor complex-associated autoantibodies with test reflex to CASPR2 and LGI1 antibodies. Antibodies are associated with acquired neuromyotonia, limbic encephalitis, painful neuropathy, Morvan syndrome, and rare tumors (eg, thymoma, small-cell lung cancer).
Quantitative Radioimmunoassay/Semi-Quantitative Indirect Fluorescent Antibody
Plain red or serum separator tube.
Separate serum from cells within 1 hour. Transfer 4 mL serum to an ARUP Standard Transport Tube. (Min: 0.5 mL)
Plasma. Severely lipemic or icteric specimens.
After separation from cells: Ambient: 72 hours; Refrigerated: 2 weeks; Frozen: 1 month (avoid repeated freeze/thaw cycles)
|2004890||Voltage-Gated Potassium Channel (VGKC) Antibody, Serum||
|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|
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 (CASPR2) instead of potassium channel antigens. A substantial number of VGKC-antibody positive cases are negative for LGI1 and CASPR 2 IgG autoantibodies, not all VGKC complex antigens are known. The clinical significance of this test can only be determined in conjunction with the patient's clinical history and related laboratory testing.
Laboratory Developed Test (LDT)
If VGKC is Indeterminate or Positive, LGI1 Antibody IgG and CASPR2 Antibody IgG will be added. 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.
83519; if reflexed add 86255 x2; if reflexed add 86256 per titer
|Component Test Code*||Component Chart Name||LOINC|
|2004890||Voltage-Gated Potassium Channel Ab, Ser||41871-5|