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HelpTest Code APBCS Adaptor Protein 3 Beta2 (AP3B2) Antibody, Cell-Binding Assay, Serum
Specimen Required
Only orderable as a reflex. For more information see:
-AIAES / Axonal Neuropathy, Autoimmune/Paraneoplastic Evaluation, Serum
-DYS2 / Dysautonomia, Autoimmune/Paraneoplastic Evaluation, Serum
-GID2 / Gastrointestinal Dysmotility, Autoimmune/Paraneoplastic Evaluation, Serum
-MAS1 / Myelopathy, Autoimmune/Paraneoplastic Evaluation, Serum
-MDS2 / Movement Disorder, Autoimmune/Paraneoplastic Evaluation, Serum
Useful For
The differential diagnosis of patients presenting with mixed cerebellar and sensory ataxia and myeloneuropathy
Evaluating AP3B2 (adaptor protein 3 beta2)-IgG by cell-binding assay using serum specimens
Testing Algorithm
If the indirect immunofluorescence (IFA) pattern suggests AP3B2 (adaptor protein 3 beta2), then this test and AP3B2 antibody IFA titer will be performed at an additional charge.
Method Name
Only orderable as a reflex. For more information see:
-AIAES / Axonal Neuropathy, Autoimmune/Paraneoplastic Evaluation, Serum
-DYS2 / Dysautonomia, Autoimmune/Paraneoplastic Evaluation, Serum
-GID2 / Gastrointestinal Dysmotility, Autoimmune/Paraneoplastic Evaluation, Serum
-MAS1 / Myelopathy, Autoimmune/Paraneoplastic Evaluation, Serum
-MDS2 / Movement Disorder, Autoimmune/Paraneoplastic Evaluation, Serum
Cell-Binding Assay (CBA)
Reporting Name
AP3B2 CBA, SSpecimen Type
SerumSpecimen Minimum Volume
See Specimen Required
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| 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
AP3B2 (adaptor protein 3 beta2)-IgG is a marker of an autoimmune disorder unified by gait instability as the predominant neurologic presentation. Patients present with either cerebellar, dorsal column, or sensory neuronal dysfunction. Clinical improvement following treatment has been reported. AP3B2 autoimmunity appears rare, is accompanied by ataxia (sensory or cerebellar), and is potentially treatable.
Reference Values
Only orderable as a reflex. For more information see:
-AIAES / Axonal Neuropathy, Autoimmune/Paraneoplastic Evaluation, Serum
-DYS2 / Dysautonomia, 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
A positive result supports a diagnosis of neurological autoimmunity. Neurological phenotypes encountered include cerebellar ataxia, spinocerebellar ataxia, myelopathy, sensory neuronopathy and autonomic neuropathy. Neurological stabilization or improvement may occur with immune therapy.
Cautions
A negative result does not exclude neurological autoimmunity or cancer.
Clinical Reference
Honorat JA, Lopez-Chiriboga AS, Kryzer, TJ, et al: Autoimmune gait disturbance accompanying adaptor protein-3B2-IgG. Neurology. 2019 Sep 3;93(10):e954-e963.
Method Description
Patient specimen is applied to a composite slide containing transfected and nontransfected HEK-293 cells. After incubation and washing, fluorescein-conjugated goat-antihuman IgG is applied to detect the presence of patient IgG binding. (Package insert: IIFT: Neurology Mosaics, Instructions for the indirect immunofluorescence test. EUROIMMUN; FA_112d-1_A_UK_C13, 02/2019)
Day(s) Performed
Monday through Sunday
Report Available
5 to 10 daysSpecimen Retention Time
28 daysPerforming 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
86255
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| APBCS | AP3B2 CBA, S | 101907-4 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 615861 | AP3B2 CBA, S | 101907-4 |