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.

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

Reflex Patterns

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

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.