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HelpTest Code CRMWC Collapsin Response-Mediator Protein-5-IgG, Western Blot, Spinal Fluid
Useful For
Evaluation of cases of chorea, vision loss, cranial neuropathy and myelopathy
Method Name
Western Blot
Reporting Name
CRMP-5-IgG Western Blot, CSFSpecimen Type
CSFOrdering Guidance
It is recommended an evaluation be ordered in conjunction with this testing if not previously performed. Multiple neurological phenotype-specific autoimmune/paraneoplastic evaluations are available. For more information as well as phenotype-specific testing options, see Autoimmune Neurology Test Ordering Guide.
Additional Testing Requirements
Shipping Instructions
Send specimen refrigerated.
Necessary Information
Provide the following information:
-Relevant clinical information
-Ordering healthcare professional name, phone number, mailing address, and e-mail address
Specimen Required
Container/Tube: Sterile vial
Specimen Volume: 3 mL
Specimen Minimum Volume
2 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| CSF | Refrigerated (preferred) | 28 days | |
| Frozen | 28 days | ||
| Ambient | 72 hours |
Reject Due To
| Gross hemolysis | Reject |
| Gross lipemia | Reject |
| Gross icterus | Reject |
Clinical Information
Autoantibodies specific for neurons and muscle are important serological markers of neurological autoimmunity. Most are highly predictive of specific neoplasms that are metastatic when diagnosed, but usually limited in spread to regional lymph nodes and adjacent structures.(1-4)
Collapsin response-mediator protein-5 (CRMP-5) is highly expressed in small-cell lung carcinomas (SCLC), in neurons throughout the adult central and peripheral nervous systems, and in a subset of glial cells.(1) In Western blot analyses, the native antigen is a 62-kDa protein (recombinant human CRMP-5 is 68 kDa).(1) CRMP-5-IgG (also known as "anti-CV-2")(4,5) is a more common autoantibody accompaniment of SCLC than antineuronal nuclear antibodies-1 (ANNA-1; anti-Hu) and sometimes occurs with thymoma.
The neurological presentation of CRMP-5 seropositive patients is usually multifocal, and can affect any level of the neuraxis. Neurological presentations that suggest a CRMP-5-IgG-related syndrome include subacute chorea or cranial neuropathy (particularly loss of vision, taste, or smell), dementia, myelopathy and gastrointestinal dysmotility in a patient with risk factors for lung cancer, or encephalopathy or neuromuscular hyperexcitability in a patient with serological or clinical evidence of myasthenia gravis.(1) Fourteen percent of patients have thromboembolic phenomena. Seropositive patients who have thymoma usually present with other myasthenia gravis neurological manifestations (eg, encephalopathy, disorders of continuous muscle fiber activity).(3)
CRMP-5-IgG is defined in serum or spinal fluid by its characteristic immunofluorescence (IF) staining pattern on a mixed tissue substrate of adult mouse central and peripheral neurons. However, CRMP-5-IgG is not detectable by standard IF screening if the titer is low (serum <1:240; CSF <1:2) or if coexisting autoantibodies, either neuron-specific or nonorgan-specific antinuclear and antimitochondrial antibodies, preclude identification of CRMP-5-IgG with certainty. In these situations, CRMP-5-IgG may be detected by Western blot analysis.
Reference Values
Negative
Interpretation
A positive result confirms that a patient's subacute neurological disorder has an autoimmune basis and is likely to be associated with a small-cell lung carcinoma (SCLC) or thymoma, which may be occult.(1,2) A positive result has a predictive value of 90% for neoplasm (77% SCLC, 6% thymoma).(1) Seropositivity is found in approximately 3% of patients who have SCLC with limited metastasis without evidence of neurological autoimmunity.(6)
Clinical-serological correlations have not yet been established for children.
Western blot analysis is indicated when interfering nonorgan-specific or coexisting neuron-specific autoantibodies in serum or spinal fluid preclude unambiguous detection of CRMP-5-IgG by indirect immunofluorescence assay, or when the immunofluorescence assay is negative in a patient whose neurological presentation suggests a CRMP-5-IgG-related syndrome.
Method Description
Western blot is performed on denatured full-length recombinant human collapsin response-mediator protein-5 (CRMP-5), reduced and subjected to electrophoresis on 10% polyacrylamide gel. IgG is detected autoradiographically by enhanced chemiluminescence.(Yu Z, Kryzer TJ, Griesmann GE, et al. CRMP-5 neuronal autoantibody: marker of lung cancer and thymoma-related autoimmunity. Ann Neurol. 2001;49[2]:146-154; Dubey D, Jitprapaikulsan J, Bi H, et al. Amphiphysin-IgG autoimmune neuropathy: A recognizable clinicopathologic syndrome. Neurology. 2019;93[20]:e1873-e1880. doi:10.1212/WNL.0000000000008472)
Day(s) Performed
Monday through Thursday
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Test Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
84182
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| CRMWC | CRMP-5-IgG Western Blot, CSF | 53707-6 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 21747 | CRMP-5-IgG Western Blot, CSF | 53707-6 |