Ordering Recommendation

Differential evaluation of encephalitis of unknown origin with subacute onset of seizures, confusion, memory loss, and/or behavioral change. Detect antibodies in addition to those included in Autoimmune Encephalitis Reflexive Panel, Serum (2013601). Testing for LGI1 and CASPR2 antibodies is always performed rather than only as a reflex. For adults and patients with suspicion of cancer, additional evaluation of paraneoplastic autoantibodies is recommended; refer to Paraneoplastic Reflexive Panel (2013955).

Mnemonic
ENCEPH EXT
Methodology

Semi-Quantitative Indirect Fluorescent Antibody/Quantitative Radioimmunoassay/Semi-Quantitative Enzyme-Linked Immunosorbent Assay

Performed

Tue

Reported

3-10 days

New York DOH Approval Status
This test is New York DOH approved.
Specimen Required
Patient Preparation
Collect

Serum Separator Tube (SST).

Specimen Preparation

Separate from cells ASAP or within 2 hours of collection. Transfer three (3) 1 mL serum aliquots to ARUP Standard Transport Tubes. (Min: 0.5 mL/aliquot)

Storage/Transport Temperature

Frozen.

Unacceptable Conditions

Contaminated specimens.

Remarks
Stability

After separation from cells: Ambient: 24 hours; Refrigerated: 1 week; Frozen: 1 month (avoid repeated freeze/thaw cycles)

Reference Interval
Test Number
Components
Reference Interval
2004221 N-methyl-D-Aspartate Receptor Antibody, IgG, Serum with Reflex to Titer < 1:10
2001771 Glutamic Acid Decarboxylase Antibody 0.0-5.0 IU/mL
2004890 Voltage-Gated Potassium Channel (VGKC) Antibody, Serum
Negative 31 pmol/L or less
Indeterminate 32-87 pmol/L
Positive 88 pmol/L or greater

2003036 Aquaporin-4 Receptor Antibody Effective October 3, 2016
Negative 2.9 U/mL or less
Positive 3.0 U/mL or greater

2013320 Aquaporin-4 Receptor Antibody, IgG by IFA with Reflex to Titer, Serum Less than 1:10
2009456 Leucine-Rich, Glioma-Inactivated Protein 1 Antibody, IgG with Reflex to Titer, Serum Less than 1:10
2009452 Contactin-Associated Protein-2 Antibody, IgG with Reflex to Titer, Serum Less than 1:10
3001260 Alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid (AMPA) Receptor Antibody, IgG by IFA with Reflex to Titer, Serum Less than 1:10
3001270 Gamma Aminobutyric Acid Receptor, Type B (GABA-BR) Antibody, IgG by IFA with Reflex to Titer, Serum Less than 1:10
3001277 Myelin Oligodendrocyte Glycoprotein (MOG) Antibody, IgG by IFA with Reflex to Titer, Serum Less than 1:10

Interpretive Data

Refer to report.

Compliance Statement D: For laboratory tests using a manufactured RUO kit. This test was developed and its performance characteristics determined by ARUP Laboratories. The U. S. Food and Drug Administration has not approved or cleared this test; however, FDA clearance or approval is not currently required for clinical use. The results are not intended to be used as the sole means for clinical diagnosis or patient management decisions.

Note

If N-methyl-D-Aspartate Receptor Antibody is positive, then a titer will be added. Additional charges apply.
If Aquaporin-4 Receptor Antibody IgG by ELISA is positive, then Aquaporin-4 Receptor Antibody, IgG by IFA will be added. If positive, then a titer will be added. Additional charges apply.
If LGI1 antibody IgG is positive, then LGI1 antibody IgG titer will be added. Additional charges apply.
If CASPR2 antibody IgG is positive, then CASPR2 antibody IgG titer will be added. Additional charges apply.
If AMPAR Antibody IgG is positive, then a titer will be added. Additional charges apply.
If GABABR Antibody IgG is positive, then a titer will be added. Additional charges apply.
If MOG Antibody IgG is positive, then a titer will be added. Additional charges apply.

Hotline History
N/A
CPT Codes

83519; 86341;
83516, if reflexed add 86255, if further reflexed add 82656;
86255 x6, if reflexed add 82656 per titer

Components
Component Test Code* Component Chart Name LOINC
2001772 Glutamic Acid Decarboxylase Antibody 56540-8
2003121 Aquaporin-4 Receptor Antibody 61430-5
2004222 N-methyl-D-Aspartate Receptor Ab, Serum 80221-5
2004890 Voltage-Gated Potassium Channel Ab, Ser 41871-5
2009453 CASPR2 Ab IgG Screen by IFA, Serum 82979-6
2009457 LGI1 Ab IgG Screen by IFA, Serum 82978-8
3001261 AMPA Receptor Ab IgG Screen, Serum 82733-7
3001271 GABA-B Receptor Ab IgG Screen, Serum 82977-0
3001278 MOG Antibody IgG Screen, Serum 91545-4
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.
Aliases
Autoimmune Encephalitis Extended Panel, Serum