Laboratory Test Guide

Autoimmune Encephalitis Panel, CSF (Sendout)

General Information

Lab Name

Autoimmune Encephalitis Panel, CSF (Sendout)

Lab Code

RCAENP

Epic Name

Autoimmune Encephalitis Panel, CSF (Sendout)

External Test Id

ENC2

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, CSF (Sendout) [RCNMDA] 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: Reflex testing may be performed at additional charge. Refer to Mayo's algorithm (linked below) for additional detail on tests and potential reflex tests included in this panel.

Ordering Guidance: Refer to Autoimmune Encephalitis Testing Recommendations or consult the Laboratory Medicine Resident on-call.

References

Synonyms

AGNA-1, AMPA-R Antibody CBA, Amphiphysin Antibody, 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 CBA, Contactin-Associated Protein-Like-2 (CASPR2) IgG, CRMP-5 IgG, Dipeptidyl-Peptidase-Like Protein-6 (DPPX) Antibody, DPPX Ab CBA, ENC1, ENC2, Encephalopathy, Encephalopathy Autoimmune Paraneoplastic Evaluation, Encephalopathy Autoimmune/Paraneoplastic Evaluation Spinal Fluid, GABA-B-R Antibody CBA, GAD65 Antibody Assay, GFAP IFA, Glutamic Acid Decarboxylase, IgLON Family Member 5 Antibody, IgLON5 Ab CBA, Leucine-Rich Glioma Inactivated Protein-1 IgG, LGI1 IgG CBA, mGluR1 Ab IFA, Neurochondrin IFA, NIF IFA, NMDA-R Antibody CBA, PCA-1, PCA-2, PCA-Tr, PDE10A IFA, Purkinje Cell Cytoplasmic Antibody Type 1, Purkinje Cell Cytoplasmic Antibody Type 2, Purkinje Cell Cytoplasmic Antibody Type Tr, Septin-7 IFA, TRIM46 IFA

Components

Code Name
RCENCI Encephalopathy, Interpretation, CSF
RIFANT IFA Notes
RCAMPA AMPA Receptor Ab CBA, CSF
RCAMPH Amphiphysin Ab, CSF
RCAGN1 Anti Glial Nuclear Ab, Type 1, CSF
RCANA1 Anti Neuronal Nuclear Ab Type 1, CSF
RCANN2 Anti Neuronal Nuclear Ab Type 2, CSF
RCANN3 Anti Neuronal Nuclear Ab Type 3, CSF
RCSPR2 CASPR2 IgG CBA, CSF
RCRMP5 CRMP 5 IgG, CSF
RCDPPC DPPX Antibody CBA, CSF
RCGABA GABA B Receptor Ab CBA, CSF
RCGD65 GAD65 Ab Assay, CSF
RCGFAP GFAP IFA, CSF
RCMGR1 mGluR1 Ab IFA, CSF
RCIG5C IgLON5 CBA, CSF
RCLGI1 LGI1 IgG CBA, CSF
RNCDIC Neurochondrin IFA, CSF
RNIFIC NIF IFA, CSF
RCNMDC NMDA Receptor Ab CBA, CSF
RCPCAT Purkinje Cell Cytoplasmc Ab Type Tr, CSF
RCPCY1 Purkinje Cell Cytoplasmic Ab Type 1, CSF
RCPCA2 Purkinje Cell Cytoplasmic Ab Type 2, CSF
RCPDE1 PDE10A Antibody IFA, CSF
RSP7IC Septin 7 IFA, CSF
RCTR46 TRIM46 Antibody IFA, CSF

Interpretation

Method

Indirect Immunofluorescence Assay (IFA): ANNA-1, ANNA-2, ANNA-3, AGNA-1, PCA-1, PCA-2, PCA-Tr, Amphiphysin Ab, CRMP-5 IgG, GFAP, mGluR1 Ab, Neurochondrin Ab, Septin-7 Antibody, PDE10A Ab, TRIM46 Ab

Cell-Binding Assay (CBA): AMPA-R Ab, GABA-B-R Ab, NMDA-R Ab CBA, LGI1-IgG CBA, CASPR2-IgG, DPPX Ab, IgLON5 Ab

Radioimmunoassay (RIA): GAD65 Ab

Reference Range

See individual components

Ref. Range Notes

Reference Values:

AMPA-R Ab CBA, CSF: Negative
Amphiphysin Ab, CSF: Negative
Anti-Glial Nuclear Ab, Type 1, CSF: Negative
Anti-Neuronal Nuclear Ab, Type 1, CSF: Negative
Anti-Neuronal Nuclear Ab, Type 2, CSF: Negative
Anti-Neuronal Nuclear Ab, Type 3, CSF: Negative
CASPR2-IgG CBA, CSF: Negative
CRMP-5-IgG, CSF: Negative
DPPX Ab CBA, CSF: Negative
GABA-B-R Ab CBA, CSF: Negative
GAD65 Ab Assay, CSF: < or =0.02 nmol/L
GFAP IFA, CSF: Negative
mGluR1 Ab IFA, CSF: Negative
IgLON5 CBA, CSF: Negative
LGI1-IgG CBA, CSF: Negative
Neurochondrin IFA, CSF: Negative
NIF IFA, CSF: Negative
NMDA-R Ab CBA, CSF: Negative
Purkinje Cell Cytoplasmc Ab Type Tr: Negative
Purkinje Cell Cytoplasmic Ab Type 1: Negative
Purkinje Cell Cytoplasmic Ab Type 2: Negative
PDE10A Ab IFA, CSF: Negative
Septin-7 IFA, CSF: Negative
TRIM46 IFA, CSF: 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, ANNA-3, 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 1:2 are detectable by recombinant CRMP-5 Western blot analysis. CRMP-5 Western blot analysis will be done on request on stored spinal fluid (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:

  • Plasma membrane autoantibodies: These are all potential effectors of neurological dysfunction: 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 acetylcholine receptor.
  • Neuronal nuclear autoantibodies: type 1 (ANNA-1), type 2 (ANNA-2), or type 3 (ANNA-3)
  • Neuronal or muscle cytoplasmic antibodies: amphiphysin, Purkinje cell antibodies (PCA-1 and PCA-2), collapsin response-mediator protein-5 (CRMP-5), or glutamic acid decarboxylase (GAD65).

Interferences and Limitations

This test is intended to be ordered for adult patients. If this test is ordered for a patient younger than 18 years of age, it will be canceled and automatically reordered by the laboratory as PCDEC/ Pediatric Autoimmune Encephalopathy/CNS Disorder Evaluation, Spinal Fluid. The pediatric autoimmune CNS disorders evaluation is part of an evolving approach to testing for autoimmune neurological disorders using phenotypic-specific evaluations that include multiple antibodies known for their disease association.

Guidelines

Ordering & Collection

Specimen Type

CSF

Collection

Collect 4 mL CSF and transfer to a sterile vial.

Approval Required

LMR approval is not required.

Handling Instructions

Outside Laboratories: Refrigerate CSF in a sterile vial.

Stability: Refrigerated (preferred): 28 days; Frozen: 28 days; Ambient: 72 hours.

Quantity

requested: 4 mL CSF
minimum: 2 mL CSF

Processing

SPS: Use container code CSF4 to route this order in Sunquest SMART.

Refrigerate CSF in a sterile vial.

  • Note: Sterile vial is preferred, but CSF samples transferred to a polypropylene aliquot will still be accepted by Mayo.

Sendouts:

  • Order Mayo Test: ENC2.
  • Interfaced: Yes.

Stability: Refrigerated (preferred): 28 days; Frozen: 28 days; Ambient: 72 hours.

Performance

LIS Dept Code

Sendouts Mayo Lab (RF) (MARF)

Performing Location(s)

Sendout Mayo Clinic Laboratories
800-533-1710

200 First Street Southwest
Rochester, MN 55901

Frequency

Performed: Monday - Sunday. Report Available: 5-10 days from sample receipt at Mayo Clinic Labs. Allow additional time for reflex testing, if performed.

Available STAT?

No

Billing & Coding

CPT codes

86255x23, 86341

Billing Comments

Reflex testing may be performed at additional charge.

LOINC

94708-5

Interfaced Order Code

UOW4080