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Test Code Enceph Encephalopathy, Autoimmune Evaluation, Serum

Useful For

Evaluating new onset encephalopathy (noninfectious or metabolic) comprising confusional states, psychosis, delirium, memory loss, hallucinations, movement disorders, sensory or motor complaints, seizures, dyssomnias, ataxias, nausea, vomiting, inappropriate antidiuresis, coma, dysautonomias, or hypoventilation in serum specimens

 

The following accompaniments should increase of suspicion for autoimmune encephalopathy:

-Headache

-Autoimmune stigmata (personal or family history or signs of diabetes mellitus, thyroid disorder, vitiligo, poliosis [premature graying], myasthenia gravis, rheumatoid arthritis, systemic lupus erythematosus)

-History of cancer

-Smoking history (20+ pack years) or other cancer risk factors

-Inflammatory cerebral spinal fluid (or isolated protein elevation)

-Neuroimaging signs suggesting inflammation

 

Evaluating limbic encephalitis (noninfectious)

 

Directing a focused search for cancer

 

Investigating encephalopathy appearing in the course or wake of cancer therapy and not explainable by metastasis or drug effect

Profile Information

Test ID Reporting Name Available Separately Always Performed
AEESI Encephalopathy, Interpretation, S No Yes
NMDCS NMDA-R Ab CBA, S No Yes
VGKC Neuronal (V-G) K+ Channel Ab, S No Yes
LG1CS LGI1-IgG CBA, S No Yes
CS2CS CASPR2-IgG CBA, S No Yes
GD65S GAD65 Ab Assay, S Yes Yes
GABCS GABA-B-R Ab CBA, S No Yes
AMPCS AMPA-R Ab CBA, S No Yes
ANN1S Anti-Neuronal Nuclear Ab, Type 1 No Yes
ANN2S Anti-Neuronal Nuclear Ab, Type 2 No Yes
ANN3S Anti-Neuronal Nuclear Ab, Type 3 No Yes
AGN1S Anti-Glial Nuclear Ab, Type 1 No Yes
PCABP Purkinje Cell Cytoplasmic Ab Type 1 No Yes
PCAB2 Purkinje Cell Cytoplasmic Ab Type 2 No Yes
PCATR Purkinje Cell Cytoplasmic Ab Type Tr No Yes
AMPHS Amphiphysin Ab, S No Yes
CCN N-Type Calcium Channel Ab No Yes
CCPQ P/Q-Type Calcium Channel Ab No Yes
ARBI ACh Receptor (Muscle) Binding Ab No Yes
GANG AChR Ganglionic Neuronal Ab, S No Yes
CRMS CRMP-5-IgG, S No Yes

Reflex Tests

Test ID Reporting Name Available Separately Always Performed
WBN Paraneoplastic Autoantibody WBlot,S No No
CRMWS CRMP-5-IgG Western Blot, S Yes No
ABLOT Amphiphysin Western Blot, S No No
NMOFS NMO/AQP4 FACS, S Yes No
NMOTS NMO/AQP4 FACS Titer, S No No
AMPIS AMPA-R Ab IF Titer Assay, S No No
GABIS GABA-B-R Ab IF Titer Assay, S No No
NMDIS NMDA-R Ab IF Titer Assay, S No No

Testing Algorithm

If indirect immunofluorescence assay (IFA) suggests ANN1S, ANN2S, ANN3S, PCAB2, PCATR, AMPHS, CRMS, or AGN1S is indeterminate, then paraneoplastic autoantibody Western blot is performed at an additional charge.

 

If client requests, or if IFA patterns suggests CRMP-5-IgG, then CRMP-5-IgG Western blot is performed at an additional charge.

 

If IFA patterns suggest amphiphysin antibody, then amphiphysin Western blot is performed at an additional charge.

 

If IFA pattern suggest NMO/AQP4-IgG, then NMO/AQP4-IgG FACS is performed at an additional charge.

 

If NMO/AQP4-IgG FACS screen assay requires further investigation, then NMO/AQP4-IgG FACS titration assay is performed at an additional charge.

 

If IFA pattern suggest NMDA-R antibody and NMDA-R antibody CBA is positive, then NMDA-R titer is performed at an additional charge.

 

If IFA pattern suggest AMPA-R antibody and AMPA-R antibody CBA is positive, then AMPA-R titer is performed at an additional charge.

 

If IFA pattern suggest GABA-B-R antibody and GABA-B-R antibody CBA is positive, then GABA-B-R titer is performed at an additional charge.

 

Western Blot: Native neuronal antigens: performed to confirm neuronal nuclear and cytoplasmic antibody specificities when IF screening is uninterpretable.

 

Recombinant human collapsin response-mediator protein 5: performed to confirm CRMP-5-IgG when IF screening is uninterpretable. Also performed for more sensitive detection of CRMP-5-IgG.

 

RIA: Confirmation of GAD65 antibodies when IF screening suggests GAD65 antibodies.

 

See Encephalopathy Autoimmune Evaluation Algorithm, Serum in Special Instructions

Method Name

ANN1S, ANN2S, ANN3S, AGN1S, PCAB2, PCATR, AMPHS, CRMS, PCABP, NMDIS, AMPIS, GABIS: Indirect Immunofluorescence Assay (IFA)

VGKC, CCN, CCPQ, GANG, GD65S, ARBI: Radioimmunoassay (RIA)

WBN, ABLOT: Western Blot

AMPCS, GABCS, NMDCS, LG1CS, CS2CS: Cell Binding Assay (CBA)

Reporting Name

Encephalopathy-Autoimmune Eval, S
Seattle Children's Hospital Note:

Clinical System Name: Autoimmune Encephalopathy Panel

Specimen Type

Serum


Necessary Information


Include relevant clinical information, name, phone number, mailing address, and e-mail address (if applicable) of ordering physician.



Specimen Required


Container/Tube:

Preferred: Red top

Acceptable: Serum gel

Specimen Volume: 4 mL


Seattle Children's Hospital Note:

Collect 4 - 8 mL whole blood in a Red Top (SST is acceptable).

Specimen Minimum Volume

2 mL

Specimen Stability Information

Specimen Type Temperature Time
Serum Refrigerated (preferred) 28 days
  Frozen  28 days
  Ambient  72 hours

Reject Due To

Hemolysis

Mild OK; Gross reject

Lipemia

Mild OK; Gross OK

Icterus

NA

Other

NA

Reference Values

NEURONAL NUCLEAR ANTIBODIES

Antineuronal Nuclear Ab, Type 1 (ANNA-1)

<1:240

Antineuronal Nuclear Ab, Type 2 (ANNA-2)

<1:240

Antineuronal Nuclear Ab, Type 3 (ANNA-3)

<1:240

Anti-Glial/Neuronal Nuclear Ab, Type 1 (AGNA-1)

<1:240

 

NEURONAL AND MUSCLE CYTOPLASMIC ANTIBODIES

Purkinje Cell Cytoplasmic Ab, Type1 (PCA-1)

<1:240

Purkinje Cell Cytoplasmic Ab, Type 2 (PCA-2)

<1:240

Purkinje Cell Cytoplasmic Ab, Type Tr (PCA-Tr)

<1:240

Amphiphysin Antibody

<1:240

CRMP-5-IgG

<1:240

 

WESTERN BLOT

Paraneoplastic Western Blot

Negative

CRMP-5-IgG Western Blot

Negative

Amphiphysin Western Blot

Negative

 

ISLET CELL ANTIBODIES

Glutamic Acid Decarboxylase (GAD65) Antibody

≤0.02 nmol/L

 

CATION CHANNEL ANTIBODIES

N-Type Calcium Channel Antibody

≤0.03 nmol/L

P/Q-Type Calcium Channel Antibody

≤0.02 nmol/L

AChR Ganglionic Neuronal Antibody

≤0.02 nmol/L

Neuronal VGKC Autoantibody

≤0.02 nmol/L

 

ACHR RECEPTOR ANTIBODIES

ACh Receptor (Muscle) Binding Antibody

≤0.02 nmol/L

 

N-Methyl-D-aspartate receptor (NMDA-R)

CBA: Negative

IFA: <1:120

2-amino-3-(5-methyl-3-oxo-1,2-oxazol-4-yl) propanoic acid receptor (AMPA-R)

CBA: Negative

IFA: <1:120

Gamma-Amino Butyric acid-type B receptor (GABA-B-R)

CBA: Negative

IFA: <1:120

LGI1-IgG CBA, S: Negative

CASPR2-IgG CBA, S: Negative          

 

Neuromyelitis Optica (NMO)/Aquaporin-4-IgG FACS Assay, S

Negative

Method Description

Indirect Immunofluorescence Assay (IFA):

Before testing, patient's serum is preabsorbed with liver powder to remove nonorgan-specific autoantibodies. After applying to a composite substrate of frozen mouse tissues (brain, kidney, and gut) and washing, fluorescein-conjugated goat-antihuman IgG is applied to detect the distribution and pattern of patient IgG binding.(Pittock SJ, Kryzer TJ, Lennon VA: Paraneoplastic antibodies coexist and predict cancer, not neurological syndrome. Ann Neurol 2004;56:715-719)

 

Radioimmunoassay (RIA):

Goat-antihuman IgG and IgM is used as precipitant in all assays. Cation channel protein antigens are solubilized from neuronal or muscle membrane, in nonionic detergent, and complexed with a selective high-affinity ligand labeled with (125)I. (125)I-labelled recombinant human glutamic acid decarboxylase-65 (GAD65) antigen is used to confirm GAD65 autoantibody (when suspected from immunofluorescent staining pattern).(Griesmann GE, Kryzer TJ, Lennon VA: Autoantibody profiles of myasthenia gravis and Lambert-Eaton myasthenic syndrome. In Manual of Clinical and Laboratory Immunology. Sixth edition. Edited by NR Rose, RG Hamilton, et al. Washington, DC, ASM Press, 2002, pp 1005-1012; Walikonis JE, Lennon VA: Radioimmunoassay for glutamic acid decarboxylase [GAD65] autoantibodies as a diagnostic aid for stiff-man syndrome and a correlate of susceptibility to type 1 diabetes mellitus. Mayo Clin Proc 1998;73[12]:1161-1166)

 

Western Blot (WB):

WB is performed when IFA screening for antineuronal nuclear antibody-type 1 (ANNA-1) is not interpretable due to interfering autoantibodies. A mixture of neuronal antigens extracted aqueously from adult rat cerebellum is denatured, reduced, and separated by electrophoresis on 10% polyacrylamide gel. Full-length recombinant human CRMP-5 antigen is used to confirm CRMP-5-IgG.(Yu Z, Kryzer TJ, Griesmann GE, et al: CRMP-5 neuronal autoantibody: marker of lung cancer and thymoma-related autoimmunity. Ann Neurol 2001;49[2]:145-154)

 

Cell Binding Assay (CBA):

Patient serum is applied to a composite slide containing transfected and nontransfected HEK-293 cells. After incubation and washing, fluorescein-conjugated goat-antihuman IgG is applied to detect the presence of patient IgG binding.(Package insert: EUROIMMUN AG. Stocker W. et al: Differenzierte Autoantikorper-Diagnostik mit BIOCHIP-Mosaiken. U Conrad, K. [Hrsg] Autoantikorper. Pabst-Verlag [1998] 78-99)

 

NMO-IgG Fluorescence-Activated Cell Sorting Assay (FACS)

Human embryonic kidney cells (HEK 293) are transfected transiently with a plasmid (pIRES2-Aequorea coerulescens green fluorescent protein [AcGFP]) encoding both green fluorescent protein (AcGFP) and AQP4-M1. After 36 hours, a mixed population of cells (transfected expressing AQP4 on the surface and AcGFP in the cytoplasm and nontransfected lacking AQP4 and AcGFP) are lifted and resuspended in live cell binding buffer. Patient serum is then added to cells at a 1 in 5 screening dilution. After incubation and washing, the cells are resuspended in secondary antibody (AlexaFluor 647–conjugated goat-antihuman IgG; 1:2000 in LCBB), held on ice, washed, fixed with 4% paraformaldehyde, and analyzed by flow cytometry (BD FACSCanto; Becton, Dickinson and Co). Two populations are gated on the basis of AcGFP expression: positive (high AQP4 expression) and negative (low or no AQP4 expression). The median Alexafluor 647 fluorescence intensity (MFI) for the AcGFP-positive population indicates relative abundance of human IgG potentially bound to AQP4 surface epitopes; MFI for the GFP-negative population indicated nonspecifically-bound IgG. The IgG binding index is calculated as the ratio of the average MFI for duplicate aliquots of each cell population (MFI GFP positive/MFI GFP negative). We established conservative cutoff IgG binding index values of 2.00 for M1-FACS.

 

If FACS assay is positive at screening dilution, FACS Titer Assay is performed at an additional charge. The patient serum is titrated to endpoint. The dilution where the IgG binding index is greater than or equal to 2, is considered the endpoint dilution. If a patient is positive at a 1:5 dilution, but negative at 1:10 dilution, the endpoint will be reported as 5.

Day(s) and Time(s) Performed

ANN1S, ANN2S, ANN3S, AGN1S, PCABP, PCAB2, PCATR, AMPHS, CRMS, AMPIS, GABIS, NMDIS:

Monday through Friday; 11:30 a.m. and 8:00 p.m.; Saturday and Sunday 8:00 a.m.

AMPCS, GABCS, NMDCS, LG1CS, CS2CS: Monday through Friday; 6 a.m.

Paraneoplastic autoantibody Western blot confirmation, CRMP-5-IgG Western blot, Amphiphysin Western blot: Monday, Wednesday, Friday; 8 a.m.

ARBI: Monday through Saturday; 5 p.m.

CCPQ, CCN, GANG, VGKC: Monday through Friday 11:00 a.m. and 6:00 p.m.; Saturday 6:00 a.m.; Sunday 6:00 a.m.

GD65S: Monday to Friday; 6:00 a.m. and 4:00 p.m.

Performing Laboratory

Mayo Medical Laboratories in Rochester

Test Classification

See Individual Test IDs

CPT Code Information

83519-ACh receptor (muscle) binding antibody

83519-AChR ganglionic neuronal antibody

83519-Neuronal VGKC autoantibody

83519-N-type calcium channel antibody

83519-P/Q-type calcium channel antibody

86255-AGNA-1

86255-Amphiphysin

86255-ANNA-1

86255-ANNA-2

86255-ANNA-3

86255-CRMP-5-IgG

86255-PCA-1

86255-PCA-2

86255-PCA-Tr

86255-AMPAR-Ab

86255-GABAR-Ab

86255-NMDAR-Ab

86341-GAD65

86255-LG1CS

86255- CS2CS

 

84182-Amphiphysin Western blot (if appropriate)

84182-CRMP-5 Western blot confirmation (if appropriate)

84182-Paraneoplastic autoantibody Western blot confirmation (if appropriate)

86255-NMO/AQP4-IgG FACS (if appropriate)

86256-AMPAR-Ab titer (if appropriate)

86256-GABAR-Ab titer (if appropriate)

86256-NMDAR-Ab titer (if appropriate)

86256- NMO/AQP4-IgG FACS titer (if appropriate)

LOINC Code Information

Test ID Test Order Name Order LOINC Value
ENS1 Encephalopathy-Autoimmune Eval, S In Process

 

Result ID Test Result Name Result LOINC Value
61516 NMDA-R Ab CBA, S No LOINC Needed
61518 AMPA-R Ab CBA, S No LOINC Needed
61519 GABA-B-R Ab CBA, S No LOINC Needed
34257 Encephalopathy, Interpretation, S 69048-7
64279 LGI1-IgG CBA, S In Process
64281 CASPR2-IgG CBA, S In Process
89080 AGNA-1, S 53709-2
81722 Amphiphysin Ab, S 33927-5
80150 ANNA-1, S 13997-2
80776 ANNA-2, S 43188-2
83137 ANNA-3, S 33924-2
8338 ACh Receptor (Muscle) Binding Ab 11034-6
81184 N-Type Calcium Channel Ab 33979-6
81185 P/Q-Type Calcium Channel Ab 33980-4
83077 CRMP-5-IgG, S 35386-2
84321 AChR Ganglionic Neuronal Ab, S 42233-7
81596 GAD65 Ab Assay, S 30347-9
83138 PCA-2, S 33925-9
9477 PCA-1, S 53717-5
83076 PCA-Tr, S 33926-7
89165 Neuronal (V-G) K+ Channel Ab, S 41871-5
36349 Reflex Added No LOINC Needed

Forms

If not ordering electronically, complete, print, and send a Neurology Specialty Testing Client Test Request (T732) with the specimen (http://www.mayomedicallaboratories.com/it-mmfiles/neurology-request-form.pdf)