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HelpTest Code MP1BC Microtubule-Associated Protein 1B (MAP1B) Antibody, Immunoblot, Spinal Fluid (Non-Orderable)
Specimen Required
Only orderable as a reflex. For more information see:
-DMC2 / Dementia, Autoimmune/Paraneoplastic Evaluation, Spinal Fluid
-ENC2 / Encephalopathy, Autoimmune/Paraneoplastic Evaluation, Spinal Fluid
-EPC2 / Epilepsy, Autoimmune/Paraneoplastic Evaluation, Spinal Fluid
-MAC1 / Myelopathy, Autoimmune/Paraneoplastic Evaluation, Spinal Fluid
-MDC2 / Movement Disorder, Autoimmune/Paraneoplastic Evaluation, Spinal Fluid
Secondary ID
621405Useful For
Only orderable as a reflex. For more information see:
DMC2 / Dementia, Autoimmune/Paraneoplastic Evaluation, Spinal Fluid
ENC2 / Encephalopathy, Autoimmune/Paraneoplastic Evaluation, Spinal Fluid
EPC2 / Epilepsy, Autoimmune/Paraneoplastic Evaluation, Spinal Fluid
MAC1 / Myelopathy, Autoimmune/Paraneoplastic Evaluation, Spinal Fluid
MDC2 / Movement Disorder, Autoimmune/Paraneoplastic Evaluation, Spinal Fluid
Detecting paraneoplastic neurological autoimmunity using spinal fluid specimens
Identifying an underlying cancer
Better characterization of a patient’s neurologic presentation
Evaluating patients with paraneoplastic or autoimmune central nervous system inflammation (brainstem encephalitis or limbic encephalitis or cerebellar ataxia or myelitis) or peripheral nervous system inflammation (including polyradiculopathy or neuropathy) and using serum or cerebrospinal fluid specimens.
Method Name
Only orderable as a reflex. For more information see:
-DMC2 / Dementia, Autoimmune/Paraneoplastic Evaluation, Spinal Fluid
-ENC2 / Encephalopathy, Autoimmune/Paraneoplastic Evaluation, Spinal Fluid
-EPC2 / Epilepsy, Autoimmune/Paraneoplastic Evaluation, Spinal Fluid
-MAC1 / Myelopathy, Autoimmune/Paraneoplastic Evaluation, Spinal Fluid
-MDC2 / Movement Disorder, Autoimmune/Paraneoplastic Evaluation, Spinal Fluid
Immunoblot (IB)
Reporting Name
MAP1B Immunoblot, CSFSpecimen Type
CSFSpecimen Minimum Volume
1 mL
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| 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
Purkinje cell cytoplasmic antibody type-2 (PCA-2) targets microtubule-associated protein 1B (MAP1B), an intracellular cytoskeletal protein expressed in neurons. MAP1B-IgG-associated paraneoplastic neuropathy typically presents as subacute or chronic polyradiculoneuropathy or sensory neuronopathy, often without pain. Approximately half of affected patients also demonstrate central nervous system involvement, including cerebellar or brainstem dysfunction, myelopathy, or cognitive symptoms. Autonomic manifestations and gastrointestinal dysmotility occur less frequently. Nearly 89% of patients with MAP1B-IgG-related neuropathy have an underlying malignancy, most commonly small-cell lung carcinoma but also squamous cell carcinoma, renal cell carcinoma, or lymphoma. When MAP1B-IgG coexists with collapsin response-mediator protein-5 (CRMP5) or antineuronal nuclear antibody (ANNA1) antibodies, malignancy detection reaches 100%, reinforcing its value as a paraneoplastic marker. Compared to ANNA1-IgG neuropathy, MAP1B-IgG disease tends to be painless with better neurological outcomes and survival. Recognition of this antibody profile aids early cancer diagnosis and guides immunotherapy or tumor-directed treatment to improve prognosis.
Reference Values
Only orderable as a reflex. For more information see:
-DMC2 / Dementia, Autoimmune/Paraneoplastic Evaluation, Spinal Fluid
-ENC2 / Encephalopathy, Autoimmune/Paraneoplastic Evaluation, Spinal Fluid
-EPC2 / Epilepsy, Autoimmune/Paraneoplastic Evaluation, Spinal Fluid
-MAC1 / Myelopathy, Autoimmune/Paraneoplastic Evaluation, Spinal Fluid
-MDC2 / Movement Disorder, Autoimmune/Paraneoplastic Evaluation, Spinal Fluid
Negative
Interpretation
When positive, this test is strongly linked to small-cell lung carcinoma, occurring in approximately 80% to 90% of microtubule-associated protein 1B (MAP1B)-positive patients who have a malignancy. It also aids diagnosis across a broad clinical spectrum, including peripheral neuropathies such as painless subacute or chronic polyradiculoneuropathy and sensory neuronopathy, as well as central nervous system disorders like cerebellar ataxia, encephalopathy, myelopathy, and brainstem or cognitive dysfunction. Autonomic features and autoimmune gastrointestinal dysmotility may also occur. Together, these findings help healthcare professionals identify when an otherwise unexplained neurological syndrome may have a paraneoplastic cause.
Method Description
Test strips are incubated with appropriately diluted sample, prepared to meet the assay's required end-dilution for each specimen type. Samples and controls are added directly to the strips, ensuring they are fully covered with dilution buffer, then mixed gently and incubated for 60 minutes at room temperature on a rocking platform. After incubation, the strips undergo a series of wash steps using diluted wash buffer, followed by a 30-minute incubation with a ready-to-use alkaline phosphatase–labeled IgG conjugate. The strips are washed again using the same procedure, then incubated with a ready-to-use substrate solution for 20 minutes at room temperature. The reaction is stopped by rinsing with distilled water through several wash cycles. Strips are then placed on absorbent material and allowed to dry fully, generally requiring at least two hours. Results are interpreted only after the strips have dried completely, and dried strips are stored protected from light.(Package insert: PCA-2 line assay. ravo Diagnostika GmbH; 05/2023)
Day(s) Performed
Varies
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 |
|---|---|---|
| MP1BC | MAP1B Immunoblot, CSF | In Process |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 621405 | MAP1B Immunoblot, CSF | In Process |