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Test Code APBCC Adaptor Protein 3 Beta2 (AP3B2) Antibody, Cell-Binding Assay, Spinal Fluid


Specimen Required


Only orderable as a part of a profile. For more information see MAC1 / Myelopathy, Autoimmune/Paraneoplastic Evaluation, Spinal Fluid

 

Container/Tube: Sterile vial

Preferred: Vial number 1

Acceptable: Any vial

Specimen Volume: 1.5 mL


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 spinal fluid 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 part of a profile. For more information see MAC1 / Myelopathy, Autoimmune/Paraneoplastic Evaluation, Spinal Fluid

 

Cell-Binding Assay (CBA)

Reporting Name

AP3B2 CBA, CSF

Specimen Type

CSF

Specimen Minimum Volume

See Specimen Required

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

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 part of a profile. For more information see MAC1 / Myelopathy, Autoimmune/Paraneoplastic Evaluation, Spinal Fluid

 

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

5 days if negative/10 days if positive

Report Available

5 to 10 days

Specimen Retention Time

28 days

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

86255

LOINC Code Information

Test ID Test Order Name Order LOINC Value
APBCC AP3B2 CBA, CSF 101907-4

 

Result ID Test Result Name Result LOINC Value
615860 AP3B2 CBA, CSF 101907-4

NY State Approved

Yes