Test Overview
Test Methodology

Quantitative RIA / Semi-quantitative IFA

Test Usage

Aid in the evaluation of muscle weakness in the context neuromuscular junction disorder with or without cancer, or the diagnosis of paraneoplastic neurological syndromes.

Reference Range *

Voltage gated potassium channel:
Negative 31 pmol/L or less
Indeterminate 32-87 pmol/L
Positive 88 pmol/L or greater
Reflex Ab:
LGI1 Less than 1:10
CASPR2 Less than 1:10

* Reference ranges may change over time. Please refer to the original patient report when evaluating results.

Test Details
Days Set Up
Analytic Time

2 - 10 days

Soft Order Code
Reference Laboratory
ARUP 2009463
Special Testing
Specimen Requirements
Collection Instructions

Collect specimen in a red top or SST tube. Centrifuge and aliquot serum into a plastic vial within 1 hour of collection. Refrigerate.

Special Handling

Must arrive in lab or aliquot within 1 hour.

Normal Volume
4 mL serum
Minimum Volume
0.5 mL serum
Storage Temperature
After separation from cells: Ambient: Less than 72 hours; Refrigerated: 2 weeks; Frozen: 1 month (avoid repeated freeze/thaw cycles).
Additional Information

If VGKC is Indeterminate or Positive, LGI1 Antibody IgG and CASPR2 Antibody IgG (LGCAR) will be added at an additional charge. If LGI1 antibody IgG is positive, then LGI1 antibody IgG titer (LGI1T) will be added at an additional charge. If CASPR2 antibody IgG is positive, then CASPR2 antibody IgG titer (CASPR) will be added at an additional charge. By ordering this test the clinician acknowledges additional reflex testing will be performed and billed at a separate additional charge if indicated. Test sent to ARUP Laboratories.

CPT Code
Fee Code
Reflex CPT
LGCAR 86255 x2, LGI1T 86256, CASPR 86256
Reflex Fee Code
LGCAR AA322, AA323; LGI1T AA324, CASPR AA325