Autoimmune Encephalitis Extended Panel, Serum, and Autoimmune Encephalitis Reflex Panel, CSF

Content Review: July 2023 Last Update:

Autoimmune encephalitis may be suspected in patients with subacute onset of new, unexplained neurologic symptoms.  Antibodies associated with autoimmune encephalitis may be present in the serum or cerebrospinal fluid (CSF) and can serve as useful markers of disease.

Disease Overview

Autoimmune encephalitis presents with diverse neurologic phenotypes, including encephalopathy, epilepsy, movement disorders, and psychiatric symptoms, among others.  The detection of antineural antibodies may help establish a diagnosis, support treatment decisions, aid prognostication, serve as a prerequisite for enrollment in clinical trials, and guide the search for an associated malignancy. Because the differential diagnosis is broad, choosing a targeted phenotypic panel based on a patient’s predominant clinical features, rather than a broad antibody panel, is often recommended. 

For more information about laboratory testing for autoimmune neurologic diseases, including detailed information about panel test selection, refer to the ARUP Consult Autoimmune Neurologic Diseases - Antineural Antibody Testing topic.

Test Description

ARUP’s serum Autoimmune Encephalitis Extended Panel and CSF Autoimmune Encephalitis Reflex Panel can be used to evaluate suspected autoimmune disease of the central nervous system (CNS). Testing for the presence of antineural antibodies in both serum and CSF is recommended in most situations. 

These panels do not test for paraneoplastic antibodies. To evaluate for paraneoplastic antibodies, refer to ARUP’s Paraneoplastic Reflexive Panels.

These panels cover a broad range of autoimmune neurologic phenotypes; for greater diagnostic yield and improved turnaround time, consider choosing a phenotype-specific panel (see table below) rather than a broad panel.

ARUP Phenotype-Specific Panels to Consider for Autoimmune Neurologic Disease
ARUP Panel
Test Code
Serum CSF

Autoimmune Encephalopathy/Dementia Panel

3006201

3006202

Autoimmune Epilepsy Panel

3006204

3006205

Autoimmune Movement Disorder Panel

3006206

3006207

Autoimmune Myelopathy Panel

3006208

3006209

Autoimmune Dysautonomia Panel

3006203

Autoimmune Pediatric CNS Disorders

3006210

3006211

Regardless of the panel chosen, order only one panel for serum and/or one panel for CSF; many antineural antibodies are redundant between these panels, and choosing based on the predominant phenotype will provide the most meaningful results. To compare these panels and the antibodies included, refer to ARUP Autoimmune Neurology Panel Components.

Testing for individual autoantibodies is also available separately and can be used for long-term monitoring.

Antibodies Tested and Methodology

Autoimmune Encephalitis Extended Panel, Serum (3006050) and Autoimmune Encephalitis Reflex Panel, CSF (3006049): Antibodies Tested and Methodology
Autoantibody Marker Method
Individual Autoantibody or Focused Panel Test Code
Serum CSF

AMPAR Ab, IgG

CBA-IFA

3001260

3001257

AQP4 Ab, IgG

CBA-IFA, reflex titer

2013320

2011699

CASPR2 Ab, IgG

CBA-IFA, reflex titer

2009452

3001986

DPPX Ab, IgG

CBA-IFA, reflex titer

3004359

3004512

GABA-AR Ab, IgG

CBA-IFA, reflex titer

3006008

3006003

GABA-BR Ab, IgG

CBA-IFA, reflex titer

3001270

3001267

GAD65 Ab

ELISA

2001771

3002788

IgLON5 Ab, IgG

CBA-IFA, reflex titer

3006018

3006013

LGI1 Ab, IgG

CBA-IFA, reflex titer

2009456

3001992

mGluR1 Ab, IgG

CBA-IFA, reflex titer

3006044

3006039

MOG Ab, IgG

CBA-IFA, reflex titer

3001277

NMDAR Ab, IgG

CBA-IFA, reflex titer

2004221

2005164

VGKC Ab, IgG

RIA

2004890

3001387

Ab, antibody; AMPAR, alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor; AQP4, aquaporin-4; CASPR2, contactin-associated protein 2; CBA, cell-binding assay/cell-based assay; DPPX, dipeptidyl-aminopeptidase-like protein 6; ELISA, enzyme-linked immunosorbent assay; GABA-AR, gamma-aminobutyric acid receptor, type A; GABA-BR, gamma-aminobutyric acid receptor, type B; GAD65, glutamic acid decarboxylase 65-kd isoform; IFA, indirect immunofluorescence assay; Ig, immunoglobulin; IgLON5; IgLON family member 5; LGI1, leucine-rich, glioma-inactivated protein 1; mGluR1, metabotropic glutamate receptor 1; MOG, myelin oligodendrocyte glycoprotein; NMDAR, N-methyl-D-aspartate receptor; RIA, radioimmunoassay; VGKC, voltage-gated potassium channel

Reflex Patterns

Autoimmune Encephalitis Extended Panel, Serum (3006050) and Reflex Panel, CSF (3006049): Reflex Patterns

Reflex patterns for Autoimmune Encephalitis Panels

Limitations

These tests do not include all known antineural antibodies:

  • Some antibodies are extremely rare or are of uncertain clinical significance.
  • As testing for newly described antibodies becomes available and their clinical relevance is established, these panels may evolve to reflect these discoveries.

Test Interpretation

Results

Results must be interpreted in the clinical context of the individual patient; test results (positive or negative) should not supersede clinical judgment.

Autoimmune Encephalitis Extended Panel, Serum (3006050) and Autoimmune Encephalitis Reflex Panel, CSF (3006049): Results Interpretation
Result Interpretation

Positive for ≥1 autoantibodies

Autoantibody(ies) detected

May support a diagnosis of autoimmune encephalitis

Consider a focused search for malignancy based on antibody-tumor associations

Negative

No autoantibodies detected

A diagnosis of autoimmune encephalitis is not excluded

References