ENCEPHALITIS PROFILE - (S)

Test Code: ENCS

Alternate Name(s):
encephalitis, encephalopathy, N-methyl-D-Aspartate Receptor Ab, NMDA/NMDA-R, AMPA Receptor Ab, AMPA/AMPA-R, Contactin-Associated, Protein 2 Ab, CASPR2, Dipeptidyl Aminopeptidase-like Protein 6 Ab, DPPX, Leucine-rich Glioma-inactivated Protein 1 Ab, LGI1, Voltage Gated Potassium Channel Ab, VGKC, GABA Receptor Ab, GABA-A/GABA-B

Test Indications: Autoantibodies against neuronal surface antigens are found in patients with autoimmune encephalopathies. The antibodies are directed against glutamate receptors (type NMDA and type AMPA), GABAB receptors, voltage-gated potassium channels (VGKC) or VGKC-associated proteins (LGI1,CASPR2, TAG-1/contactin-2). Since these antigens play a direct or indirect role in synaptic signal transduction and plasticity, the associated autoimmunities manifest with seizures and neuropsychiatric symptoms. The resulting conditions include special forms of autoimmune limbic encephalitis, neuromyotonia or Morvan’s syndrome.

Restricted to Neurologists or via prior approval.
Complete the pre-approval form by clicking on the following link:
 

Immunology/Hematology Approval for Test Referral

_SH Approval for Test Referral Immunology and Hematology F150-100-100

_SH Immunology Autoimmune Laboratory Requisition (R250-10-85)

Reference Intervals:
<1:10 Titre (Negative)
(CASPR2 is reported as borderline at 1:10 and 1:32 titre)
A negative result does not necessarily exclude autoimmune disease.  Positive results should not be interpreted in isolation and must be correlated with relevant clinical findings. 

The Method of Analysis:
The indirect immunofluorescence test (IIFT) utilizes transfected cells to detect antibodies against:
• Glutamate Receptor (type NMDA)
• Glutamate Receptor (type AMPA1/2)
• Contactin-Associated Protein 2 (CASPR2)
• Dipeptidyl Aminopeptidase-like Protein 6 (DPPX)
• Leucine-rich Glioma-inactivated Protein 1 (LGI1)
• GABAB Receptor (GABARB1/B2)
in patient samples.  Cells are incubated with diluted patient sample. If the reaction is positive, specific antibodies of classes IgA, IgG, and IgM attach to the antigens. In a second step, the attached antibodies are stained with fluorescein-labelled anti-human IgG antibodies and made visible with a fluorescence microscope.  Testing supports the diagnosis of neurological diseases (encephalitis).

References:
EUROIMMUN IIFT: Neurology Mosaics EUROPattern Instructions for the indirect immunofluorescence test FC_112d-1_A_UK_C07.doc Version 28/01/2019.
 

Weekdays

TAT Within 5 days. Ordering restricted to Neurologists or by prior approval.

Positive results will be accompanied by a titre.
 
A negative result does not exclude the presence of autoantibodies.  If clinical suspicion remains high, testing in CSF should be considered.