Test Code MP1BS Microtubule-Associated Protein 1B (MAP1B) Antibody, Immunoblot, Serum (Non-Orderable)

Specimen Required

Only orderable as a reflex. For more information see:

-AIAES / Axonal Neuropathy, Autoimmune/Paraneoplastic Evaluation, Serum

-DMS2 / Dementia, Autoimmune/Paraneoplastic Evaluation, Serum

-DYS2 / Dysautonomia, Autoimmune/Paraneoplastic Evaluation, Serum

-ENS2 / Encephalopathy, Autoimmune/Paraneoplastic Evaluation, Serum

-EPS2 / Epilepsy, Autoimmune/Paraneoplastic Evaluation, Serum

-GID2 / Gastrointestinal Dysmotility, Autoimmune/Paraneoplastic Evaluation, Serum

-MAS1 / Myelopathy, Autoimmune/Paraneoplastic Evaluation, Serum

-MDS2 / Movement Disorder, Autoimmune/Paraneoplastic Evaluation, Serum

Secondary ID

621406

Useful For

Only orderable as a reflex. For more information see:

AIAES / Axonal Neuropathy, Autoimmune/Paraneoplastic Evaluation, Serum

DMS2 / Dementia, Autoimmune/Paraneoplastic Evaluation, Serum

DYS2 / Dysautonomia, Autoimmune/Paraneoplastic Evaluation, Serum

ENS2 / Encephalopathy, Autoimmune/Paraneoplastic Evaluation, Serum

EPS2 / Epilepsy, Autoimmune/Paraneoplastic Evaluation, Serum

GID2 / Gastrointestinal Dysmotility, Autoimmune/Paraneoplastic Evaluation, Serum

MAS1 / Myelopathy, Autoimmune/Paraneoplastic Evaluation, Serum

MDS2 / Movement Disorder, Autoimmune/Paraneoplastic Evaluation, Serum

Detecting paraneoplastic neurological autoimmunity using serum 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:

-AIAES / Axonal Neuropathy, Autoimmune/Paraneoplastic Evaluation, Serum

-DMS2 / Dementia, Autoimmune/Paraneoplastic Evaluation, Serum

-DYS2 / Dysautonomia, Autoimmune/Paraneoplastic Evaluation, Serum

-ENS2 / Encephalopathy, Autoimmune/Paraneoplastic Evaluation, Serum

-EPS2 / Epilepsy, Autoimmune/Paraneoplastic Evaluation, Serum

-GID2 / Gastrointestinal Dysmotility, Autoimmune/Paraneoplastic Evaluation, Serum

-MAS1 / Myelopathy, Autoimmune/Paraneoplastic Evaluation, Serum

-MDS2 / Movement Disorder, Autoimmune/Paraneoplastic Evaluation, Serum

Immunoblot (IB)

Reporting Name

MAP1B Immunoblot, S

Specimen Type

Serum

Specimen Minimum Volume

Serum:1 mL

Specimen Stability Information

Specimen Type	Temperature	Time
Serum	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:

-AIAES / Axonal Neuropathy, Autoimmune/Paraneoplastic Evaluation, Serum

-DMS2 / Dementia, Autoimmune/Paraneoplastic Evaluation, Serum

-DYS2 / Dysautonomia, Autoimmune/Paraneoplastic Evaluation, Serum

-ENS2 / Encephalopathy, Autoimmune/Paraneoplastic Evaluation, Serum

-EPS2 / Epilepsy, Autoimmune/Paraneoplastic Evaluation, Serum

-GID2 / Gastrointestinal Dysmotility, Autoimmune/Paraneoplastic Evaluation, Serum

-MAS1 / Myelopathy, Autoimmune/Paraneoplastic Evaluation, Serum

-MDS2 / Movement Disorder, Autoimmune/Paraneoplastic Evaluation, Serum

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 syndromes 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
MP1BS	MAP1B Immunoblot, S	In Process

Result ID	Test Result Name	Result LOINC Value
621406	MAP1B Immunoblot, S	In Process