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HelpTest Code PC2TC Purkinje Cell Cytoplasmic Antibody Type 2 (PCA-2) Titer, Spinal Fluid
Ordering Guidance
Serum is preferred. Spinal fluid testing is particularly useful when interfering antibodies are present in the serum.
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
-MDC2 / Movement Disorder, Autoimmune/Paraneoplastic Evaluation, Spinal Fluid
-MAC1 / Myelopathy, Autoimmune/Paraneoplastic Evaluation, Spinal Fluid
Container/Tube: Sterile vial
Specimen Volume: 4 mL
Useful For
Evaluating patients who present with a subacute neurological disorder of undetermined etiology and have risk factors for lung cancer
Reporting an end titer result from spinal fluid specimens
Testing Algorithm
If the indirect immunofluorescence pattern suggests Purkinje cell cytoplasmic antibody type 2 (PCA-2), then this test will be performed at an additional charge.
Reporting Name
PCA-2 Titer, CSFSpecimen Type
CSFSpecimen Minimum Volume
2 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 |
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
-MDC2 / Movement Disorder, Autoimmune/Paraneoplastic Evaluation, Spinal Fluid
-MAC1 / Myelopathy, Autoimmune/Paraneoplastic Evaluation, Spinal Fluid
<1:2
Neuron-restricted patterns of IgG staining that do not fulfill criteria for Purkinje cell cytoplasmic antibody type 2 may be reported as "unclassified antineuronal IgG." Complex patterns that include non-neuronal elements may be reported as "uninterpretable."
Supportive Data
Purkinje cell autoantibody type-2 (PCA-2) binds to the cytoplasm of cerebellar neurons in a characteristic pattern. Western blots of reduced/denatured cerebellar and small-cell lung carcinoma proteins reveal a common antigenic band, approximately 280 kDa.(1) Nine of 10 seropositive patients initially identified had a subacute neurological presentation (elements of encephalomyeloneuropathy) and 9 of 10 had lung cancer confirmed.(1) Similar neurological and oncological correlations have been observed in 30 subsequently identified seropositive patients.(Lennon VA: Unpublished data)
Method Description
The patient's specimen is tested by a standardized immunofluorescence assay that uses a composite frozen section of mouse cerebellum, kidney, and gut tissues. After incubation with the specimen and washing, fluorescein-conjugated goat-antihuman IgG is applied. Neuron-specific autoantibodies are identified by their characteristic fluorescence staining patterns. Specimens that are scored positive for any neuronal nuclear or cytoplasmic autoantibody are titrated. Interference by coexisting non-neuron-specific autoantibodies can usually be eliminated by serologic absorption.(Honorat JA, Komorowski L, Josephs KA, et al. IgLON5 antibody: Neurological accompaniments and outcomes in 20 patients. Neurol Neuroimmunol Neuroinflamm. 2017;4[5]:e385. Published 2017 Jul 18. doi:10.1212/NXI.0000000000000385)
Day(s) Performed
Monday through Sunday
Report Available
6 to 8 daysSpecimen Retention Time
2 daysPerforming Laboratory
Mayo Clinic Laboratories in Rochester
CPT Code Information
86256
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| PC2TC | PCA-2 Titer, CSF | 94364-7 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 43447 | PCA-2 Titer, CSF | 94364-7 |