Autoimmune Encephalitis Panel, Serum (Sendout)
General Information
- Lab Name
- Autoimmune Encephalitis Panel, Serum (Sendout)
- Lab Code
- RSAENP
- Epic Name
- Autoimmune Encephalitis Panel, Serum (Sendout)
- External Test Id
- ENS2
- Description
Test Information: Encephalitis is a debilitating neurologic condition caused by infectious and autoimmune conditions that result in inflammation of the brain parenchyma. The identification of autoantibodies may augment a diagnosis of autoimmune encephalitis, but is not required for the diagnosis or initiation of therapy. The most frequently identified antibodies target NMDA-R. We recommend ordering NMDA Receptor IgG Antibody with Reflex, Serum (Sendout) [RNMDA] as first-line testing for autoimmune encephalitis prior to ordering this full panel.
Monitoring titers over time for these antibodies is not recommended; however, this recommendation is based on limited currently available literature.
Test Algorithm: Refer to Mayo's algorithm (linked below) for additional detail on tests and potential reflex tests included in this panel. Reflex testing may be performed at additional charge.
Ordering Guidance: Refer to Autoimmune Encephalitis Testing Recommendations or consult the Laboratory Medicine Resident on-call.
- The Mayo Antibody Prevalence in Epilepsy and Encephalopathy (APE²) Scorecard may be used to determine the likelihood of neural antibody positivity in patients with encephalopathy and/or seizures.
Ordering Requirements: Orders from UW Medicine Neurology Clinics are pre-approved. For all other orders, Laboratory Medicine Resident (LMR) approval is required.
- References
- Mayo Clinical & Interpretive Information: Encephalopathy, Autoimmune/Paraneoplastic Evaluation, Serum
- Synonyms
- AGNA-1, AMPA-R Ab CBA, Amphiphysin Ab, ANNA-1, ANNA-2, ANNA-3, Anti-Glial Nuclear Antibody, Anti-Neuronal Nuclear Antibody Type 1, Anti-Neuronal Nuclear Antibody Type 2, Anti-Neuronal Nuclear Antibody Type 3, CASPR2 IgG, Contactin-Associated Protein-Like-2 (CASPR2) IgG, CRMP-5 IgG, Dipeptidyl-Peptidase-Like Protein-6 (DPPX) Antibody, DPPX, Encephalitis, Encephalopathy, Encephalopathy Autoimmune Paraneoplastic Evaluation, Encephalopathy Autoimmune/Paraneoplastic Evaluation Serum, ENS2, GABA-B-R Antibody CBA, GAD65, GFAP, Glutamic Acid Decarboxylase, IgLON Family Member 5 Antibody, IGLON5, Leucine-Rich Glioma Inactivated Protein-1 IgG, LGI1 IgG, Limbic encephalitis, Neurochondrin, NIF, NMDA-R Ab CBA, PCA-1, PCA-2, PCA-Tr, PDE10A, Phosphodiesterase 10A (PDE10A) IgG, Purkinje Cell Cytoplasmc Antibody Type Tr, Purkinje Cell Cytoplasmic Antibody Type 1, Purkinje Cell Cytoplasmic Antibody Type 2, Septin-7, TRIM46, Tripartite Motif-Containing Protein 46 (TRIM46) IgG
- Components
-
Code Name RAEESI Encephalopathy Interpretation, Serum RAESIF IFA Notes RAMPCS AMPA-R Antibody CBA RAMPHS Amphiphysin Antibody RAGNA1 Anti Glial Nuclear Antibody 1 RANN1 Anti Neuronal Nuclear Antibody 1 RANN2 Anti Neuronal Nuclear Antibody 2 RANN3 Anti Neuronal Nuclear Antibody 3 RCS2CS CASPR2 IgG CBA RCRMP CRMP 5 IgG RDPPCS DPPX Antibody CBA RGABCS GABA B R Antibody CBA RGAD65 GAD65 Antibody Assay RGFAIS GFAP IFA RIG5CS IgLON5 CBA RLG1CS LGI1 IgG CBA RMGL1S mGluR1 Antibody IFA RNCDIS Neurochondrin IFA RNIFIS NIF IFA RNMDCS NMDA R Antibody CBA RPCA1 Purkinje Cell Cytoplasmic Antibody 1 RPCA2 Purkinje Cell Cytoplasmic Antibody 2 RPCATR Purkinje Cell Cytoplasmic Antibody Tr RPDEIS PDE10A Antibody IFA RSP7IS Septin 7 IFA RTRM46 TRIM46 Antibody IFA
Interpretation
- Guidelines
- Method
Immunofluorescence assay (IFA): Amphiphysin Ab, Anti-Glial Nuclear Ab Type 1, Anti-Neuronal Nuclear Ab Type 1, Anti-Neuronal Nuclear Ab Type 2, Anti-Neuronal Nuclear Ab Type 3, CRMP-5-IgG, GFAP, mGluR1 Ab, Neurochondrin, NIF, Purkinje Cell Cytoplasmic Ab Type 1, Purkinje Cell Cytoplasmic Ab Type 2, Purkinje Cell Cytoplasmic Ab Type Tr, Septin-7, TRIM46 Ab, PDE10A Ab.
Cell-binding assay (CBA): AMPA-R Ab, CASPR2-IgG, GABA-B-R Ab, LGI1-IgG, NMDA-R Ab, IgLON5 Ab, DPPX Ab.
Radioimmunoassay (RIA): GAD65 Ab Assay
- Reference Range
- See individual components
- Ref. Range Notes
Reference Values:
AMPA-R Ab CBA: Negative Amphiphysin Ab: Negative Anti-Glial Nuclear Ab, Type 1: Negative Anti-Neuronal Nuclear Ab, Type 1: Negative Anti-Neuronal Nuclear Ab, Type 2: Negative Anti-Neuronal Nuclear Ab, Type 3: Negative CASPR2-IgG CBA: Negative CRMP-5-IgG: Negative DPPX Ab CBA: Negative GABA-B-R Ab CBA: Negative GAD65 Ab Assay: < or =0.02 nmol/L GFAP IFA: Negative mGluR1 Ab IFA: Negative IgLON5 CBA: Negative LGI1-IgG CBA: Negative Neurochondrin IFA: Negative NIF IFA: Negative NMDA-R Ab CBA: Negative Purkinje Cell Cytoplasmic Ab Type 1: Negative Purkinje Cell Cytoplasmic Ab Type 2: Negative Purkinje Cell Cytoplasmic Ab Type Tr: Negative PDE10A Ab IFA: Negative Septin-7 IFA: Negative TRIM46 IFA: Negative Note: Includes reference values for panel tests only.
Neuron-restricted patterns of IgG staining that do not fulfill criteria for ANNA-1, ANNA-2, CRMP-5-IgG, PCA-1, PCA-2, or PCA-Tr may be reported as "unclassified anti-neuronal IgG." Complex patterns that include nonneuronal elements may be reported as "uninterpretable."
CRMP-5 titers lower than 1:240 are detectable by recombinant CRMP-5 Western blot analysis. CRMP-5 Western blot analysis will be done on request on stored serum (held 4 weeks). This supplemental testing is recommended in cases of chorea, vision loss, cranial neuropathy, and myelopathy. Call the Neuroimmunology Laboratory at 800-533-1710 to request CRMP-5 Western blot.
Interpretation: Neuronal, glial, and muscle autoantibodies are valuable serological markers of autoimmune encephalopathy and of a patient's immune response to cancer. These autoantibodies are usually accompanied by subacute neurological symptoms and signs are not found in healthy subjects. It is not uncommon for more than 1 of the following autoantibody specificities to be detected in patients with an autoimmune encephalopathy:
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Plasma membrane autoantibodies: N-methyl-D-aspartate (NMDA) receptor; 2-amino-3-(5-methyl-3-oxo-1,2- oxazol-4-yl) propanoic acid (AMPA) receptor; gamma-amino butyric acid (GABA-B) receptor; neuronal ACh receptor. These are all potential effectors of neurological dysfunction.
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Neuronal nuclear autoantibodies, type 1 (ANNA-1), type 2 (ANNA-2), or type 3 (ANNA-3)
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Neuronal or muscle cytoplasmic antibodies: amphiphysin, Purkinje cell antibodies (PCA-1) and PCA-2, CRMP-5, GAD65, or striational
-
- Interferences and Limitations
Cautions:
Negative results do not exclude autoimmune encephalopathy or cancer.
This test does not detect Ma1 or Ma2 antibodies (also known as MaTa), which are sometimes associated with brainstem and limbic encephalitis in the context of testicular germ cell neoplasms. Scrotal ultrasound is advised for men who present with unexplained subacute encephalitis. To order Ma2 Antibody, refer to separate test guide #577.
Intravenous immunoglobulin (IVIg) treatment prior to the serum collection may cause a false-positive result.
- References
- Mayo Clinical & Interpretive Information: Encephalopathy, Autoimmune/Paraneoplastic Evaluation, Serum
Ordering & Collection
- Specimen Type
- Blood
- Collection
-
12 mL blood in RED TOP or GOLD SST tubes
- Approval Required
- Orders from UW Medicine Neurology Clinics are pre-approved. For all other orders, Laboratory Medicine Resident (LMR) approval is required.
- Handling Instructions
Outside Laboratories: Centrifuge samples and transfer serum to a separate plastic vial. Refrigerate serum while awaiting shipment. Transport with a cold pack.
Stability: Refrigerated (preferred): 28 days; Frozen: 28 days; Ambient: 72 hours.
Reject Due To: Gross hemolysis, gross lipemia, gross icterus, insufficient sample volume.
- Quantity
-
Requested: 4 mL serum
Minimum: 2.5 mL serum
Processing
- Receiving Instructions
Centrifuge samples and transfer 4 mL serum (2.5 mL minimum) to a separate plastic aliquot. Refrigerate serum.
Sendouts:
- Order Mayo Test: ENS2
- Interfaced: Yes [Interface: 601; Worksheet: MARF]
Stability: Refrigerated (preferred): 28 days; Frozen: 28 days; Ambient: 72 hours.
Reject Due To: Gross hemolysis, gross lipemia, gross icterus, insufficient sample volume.
- Misc Sendout
Performance
- Lab Department
- Sendouts Mayo Lab (RF)(MARF)
- Frequency
- Performed: Varies. Report available: 10-13 days from sample receipt at Mayo Clinic Laboratories.
- Available STAT?
- No
- Performing Location(s)
-
Sendout Mayo Clinic Laboratories
800-533-1710200 First Street Southwest
Rochester, MN 55901
Billing & Coding
- CPT Codes
- 86255x23, 86341
- LOINC
- 94697-0
- Interfaced Order Code
- UOW4912
- Billing Comments
Reflex testing may be performed at additional charge.