Contactin-Associated Protein-2 Antibody, IgG with Reflex to Titer, CSF
Ordering Recommendation

Aid in diagnosis of contactin associated protein 2 (CASPR2) antibody disorders associated with acquired neuromyotonia, limbic encephalitis, painful neuropathy, and Morvan syndrome. Use to manage antibody-positive (CASPR2) individual following immunotherapy and/or plasmapheresis. Serum is the preferred specimen; see Contactin-Associated Protein-2 Antibody, IgG with Reflex to Titer, Serum (2009452).

Semi-Quantitative Indirect Fluorescent Antibody
1-8 days
New York DOH Approval Status
This test is New York DOH approved.
Submit With Order
ARUP Consult®
Disease Topics
Specimen Required
Patient Preparation
Specimen Preparation
Transfer 0.5 mL CSF to an ARUP Standard Transport Tube. (Min: 0.15 mL) 
Storage/Transport Temperature
Unacceptable Conditions
Contaminated, hemolyzed, or severely lipemic specimens. 
Ambient: 48 hours; Refrigerated: 2 weeks; Frozen: 1 month 
Reference Interval
Less than 1:1
Interpretive Data
Contactin-associated protein-2 (CASPR2) IgG antibody may occur as part of the voltage-gated potassium channel (VGKC) complex antibodies.

The presence of CASPR2 IgG antibody is associated with a wide spectrum of clinical manifestations, including acquired neuromyotonia, limbic encephalitis, painful neuropathy, and Morvan syndrome. Tumors such as thymoma, small cell lung cancer, and other rarer tumors may occur. The full-spectrum of clinical disorders and tumors associated with the CASPR2 IgG antibody continues to be defined. Results should be interpreted in correlation with the patient's clinical history and other laboratory findings.

This indirect fluorescent antibody assay utilizes contactin-associated protein-2 (CASPR2) transfected cell lines for the detection and semi-quantification of the CASPR2 IgG antibody.

Compliance Statement D: For laboratory tests using a manufactured RUO kit. 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.

If CASPR2 antibody IgG is positive, then CASPR2 antibody IgG titer will be added. Additional charges apply.
Hotline History
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CPT Code(s)
Component Test Code*Component Chart NameLOINC
3001987CASPR2 Ab IgG Screen by IFA, CSF90820-2
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