Test Code ENS2M Encephalopathy, Autoimmune Evaluation, Serum
Additional Codes
MAYO: ENS2
EPIC: LAB1895
Necessary Information
Provide the following information:
-Relevant clinical information
-Ordering provider name, phone number, mailing address, and e-mail address
Specimen Required
Patient Preparation:
1. For optimal antibody detection, specimen collection is recommended prior to initiation of immunosuppressant medication.
2. This test should not be requested in patients who have recently received radioisotopes, therapeutically or diagnostically, because of potential assay interference. The specific waiting period before specimen collection will depend on the isotope administered, the dose given, and the clearance rate in the individual patient. Specimens will be screened for radioactivity prior to analysis. Radioactive specimens received in the laboratory will be held 1 week and assayed if sufficiently decayed, or canceled if radioactivity remains.
3. Patient should have no general anesthetic or muscle-relaxant drugs in the previous 24 hours.
Container/Tube:
Preferred: Red top
Acceptable: Serum gel
Specimen Volume: 4 mL
Forms
If not ordering electronically, complete, print, and send a Neurology Specialty Testing Client Test Request (T732) with the specimen.
Secondary ID
92116Useful 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 |
GANG | AChR Ganglionic Neuronal Ab, S | No | Yes |
AMPCS | AMPA-R Ab CBA, S | No | Yes |
AMPHS | Amphiphysin Ab, S | No | Yes |
AGN1S | Anti-Glial Nuclear Ab, Type 1 | 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 |
CS2CS | CASPR2-IgG CBA, S | No | Yes |
CRMS | CRMP-5-IgG, S | No | Yes |
DPPIS | DPPX Ab IFA, S | No | Yes |
GABCS | GABA-B-R Ab CBA, S | No | Yes |
GD65S | GAD65 Ab Assay, S | Yes | Yes |
GFAIS | GFAP IFA, S | No | Yes |
IG5IS | IgLON5 IFA, S | No | Yes |
LG1CS | LGI1-IgG CBA, S | No | Yes |
GL1IS | mGluR1 Ab IFA, S | No | Yes |
NIFIS | NIF IFA, S | No | Yes |
NMDCS | NMDA-R Ab CBA, S | No | Yes |
CCN | N-Type Calcium Channel Ab | No | Yes |
CCPQ | P/Q-Type Calcium Channel Ab | 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 |
Reflex Tests
Test ID | Reporting Name | Available Separately | Always Performed |
---|---|---|---|
ARBI | ACh Receptor (Muscle) Binding Ab | Yes | No |
ARMO | ACh Receptor (Muscle) Modulating Ab | No | No |
AGNBS | AGNA-1 Immunoblot, S | No | No |
AINCS | Alpha Internexin CBA, S | No | No |
AMPIS | AMPA-R Ab IF Titer Assay, S | No | No |
AMIBS | Amphiphysin Immunoblot, S | No | No |
AN1BS | ANNA-1 Immunoblot, S | No | No |
AN2BS | ANNA-2 Immunoblot, S | No | No |
CRMWS | CRMP-5-IgG Western Blot, S | Yes | No |
DPPCS | DPPX Ab CBA, S | No | No |
DPPTS | DPPX Ab IFA Titer, S | No | No |
GABIS | GABA-B-R Ab IF Titer Assay, S | No | No |
GFACS | GFAP CBA, S | No | No |
GFATS | GFAP IFA Titer, S | No | No |
IG5CS | IgLON5 CBA, S | No | No |
IG5TS | IgLON5 IFA Titer, S | No | No |
GL1CS | mGluR1 Ab CBA, S | No | No |
GL1TS | mGluR1 Ab IFA Titer, S | No | No |
NFHCS | NIF Heavy Chain CBA, S | No | No |
NIFTS | NIF IFA Titer, S | No | No |
NFLCS | NIF Light Chain CBA, S | No | No |
NMDIS | NMDA-R Ab IF Titer Assay, S | No | No |
PC1BS | PCA-1 Immunoblot, S | No | No |
PCTBS | PCA-Tr Immunoblot, S | No | No |
Testing Algorithm
If client requests or if immunofluorescence (IFA) patterns suggest CRMP-5-IgG, then CRMP-5-IgG Western blot, ACh receptor (muscle) binding antibody, and ACh receptor (muscle) modulating antibody are performed at an additional charge.
If IFA patterns suggest amphiphysin antibody, then amphiphysin immunoblot is performed at an additional charge.
If IFA pattern suggests AGNA-1 antibody, then AGNA-1 immunoblot is performed at an additional charge.
If IFA pattern suggests ANNA-1 antibody, then ANNA-1 immunoblot is performed at an additional charge.
If IFA pattern suggests ANNA-2 antibody, then ANNA-2 immunoblot is performed at an additional charge.
If IFA pattern suggests PCA-1 antibody, then PCA-1 immunoblot is performed at an additional charge.
If IFA pattern suggests PCA-Tr antibody, then PCA-Tr immunoblot is performed at an additional charge.
If IFA pattern suggests IgLON5 antibody, then IgLON5 IFA titer and IgLON5 cell-binding assay (CBA) is performed at an additional charge.
If IFA pattern suggests AMPA-receptor antibody, and AMPA-receptor antibody CBA is positive, then AMPA-receptor antibody IFA titer assay is performed at an additional charge.
If AMPA-receptor antibody CBA is positive, then CRMP-5-IgG Western blot, ACh receptor (muscle) binding antibody, and ACh receptor (muscle) modulating antibody are performed at an additional charge.
If CASPR2-receptor antibody CBA is positive, then CRMP-5-IgG Western blot, ACh receptor (muscle) binding antibody, and ACh receptor (muscle) modulating antibody are performed at an additional charge.
If IFA pattern suggests GABA-B-receptor antibody, and GABA-B-receptor antibody is positive, then GABA-B-receptor antibody IFA titer assay is performed at an additional charge.
If IFA pattern suggests GFAP antibody, then GFAP IFA titer and GFAP CBA are performed at an additional charge.
If IFA pattern suggests NMDA-receptor antibody, and NMDA-receptor antibody CBA is positive, then NMDA-receptor antibody IFA titer assay is performed at an additional charge.
If IFA pattern suggests DPPX antibody, then DPPX antibody CBA and DPPX titer are performed at an additional charge.
If IFA pattern suggests mGluR1 antibody, then mGluR1 antibody CBA and mGluR1 titer are performed at an additional charge.
If IFA pattern suggests NIF antibody, then alpha internexin CBA, NIF heavy chain CBA, NIF light chain CBA, and NIF titer are performed at an additional charge.
See Encephalopathy Autoimmune Evaluation Algorithm-Serum in Special Instructions.
Special Instructions
Method Name
AGN1S, AMPHS, AMPIS, ANN1S, ANN2S, ANN3S, CRMS, DPPIS, DPPTS, GABIS, GFAIS, GFATS, GL1IS, GL1TS, IG5IS, IG5TS, NIFIS, NIFTS, NMDIS, PCAB2, PCABP, PCATR: Indirect Immunofluorescence Assay (IFA)
AINCS, AMPCS, CS2CS, DPPCS, GABCS, GFACS, GL1CS, IG5CS, LG1CS, NFHCS, NFLCS, NMDCS: Cell-Binding Assay (CBA)
CRMWS: Western Blot (WB)
AGNBS, AMIBS, AN1BS, AN2BS, PC1BS, PCTBS: Immunoblot (IB)
ARBI, CCN, CCPQ, GANG, GD65S: Radioimmunoassay (RIA)
ARMO: Live Cell Assay (LCA)
Reporting Name
Encephalopathy-Autoimmune Eval, SSpecimen Type
SerumSpecimen Minimum Volume
2.5 mL
Specimen Stability Information
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Serum | Refrigerated (preferred) | 28 days | |
Frozen | 28 days | ||
Ambient | 72 hours |
Reject Due To
Gross hemolysis | Reject |
Gross lipemia | Reject |
Gross icterus | Reject |
Reference Values
Test ID |
Reporting name |
Methodology |
Reference value |
GANG |
AChR Ganglionic Neuronal Ab, S |
Radioimmunoassay (RIA) |
≤0.02 nmol/L |
AMPCS |
AMPA-R Ab CBA, S |
Cell-binding assay (CBA) |
Negative |
AMPHS |
Amphiphysin Ab, S |
Indirect Immunofluorescence Assay (IFA) |
<1:240 |
AGN1S |
Anti-Glial Nuclear Ab, Type 1 |
IFA |
<1:240 |
ANN1S |
Anti-Neuronal Nuclear Ab, Type 1 |
IFA |
<1:240 |
ANN2S |
Anti-Neuronal Nuclear Ab, Type 2 |
IFA |
<1:240 |
ANN3S |
Anti-Neuronal Nuclear Ab, Type 3 |
IFA |
<1:240 |
CS2CS |
CASPR2-IgG CBA, S |
CBA |
Negative |
CRMS |
CRMP-5-IgG, S |
IFA |
<1:240 |
DPPIS |
DPPX Ab IFA, S |
IFA |
Negative |
GABCS |
GABA-B-R Ab CBA, S |
CBA |
Negative |
GD65S |
GAD65 Ab Assay, S |
RIA |
≤0.02 nmol/L Reference values apply to all ages. |
GFAIS |
GFAP IFA, S |
IFA |
Negative |
IG5IS |
IgLON5 IFA, S |
IFA |
Negative |
LG1CS |
LGI1-IgG CBA, S |
CBA |
Negative |
GL1IS |
mGluR1 Ab IFA, S |
IFA |
Negative |
NIFIS |
NIF IFA, S |
IFA |
Negative |
NMDCS |
NMDA-R Ab CBA, S |
CBA |
Negative |
CCN |
N-Type Calcium Channel Ab |
RIA |
≤0.03 nmol/L |
CCPQ |
P/Q-Type Calcium Channel Ab |
RIA |
≤0.02 nmol/L |
PCABP |
Purkinje Cell Cytoplasmic Ab Type 1 |
IFA |
<1:240 |
PCAB2 |
Purkinje Cell Cytoplasmic Ab Type 2 |
IFA |
<1:240 |
PCATR |
Purkinje Cell Cytoplasmic Ab Type Tr |
IFA |
<1:240 |
Reflex Information:
Test ID |
Reporting name |
Methodology |
Reference value |
ARBI |
ACh Receptor (Muscle) Binding Ab |
RIA |
≤0.02 nmol/L |
ARMO |
ACh Receptor (Muscle) Modulating Ab |
Live-cell assay (LCA) |
0-20% (reported as __% loss of AChR) |
AGNBS |
AGNA-1 Immunoblot, S |
Immunoblot (IB) |
Negative |
AINCS |
Alpha Internexin CBA, S |
CBA |
Negative |
AMPIS |
AMPA-R Ab IF Titer Assay, S |
IFA |
<1:120 |
AMIBS |
Amphiphysin Immunoblot, S |
IB |
Negative |
AN1BS |
ANNA-1 Immunoblot, S |
IB |
Negative |
AN2BS |
ANNA-2 Immunoblot, S |
IB |
Negative |
CRMWS |
CRMP-5-IgG Western Blot, S |
Western blot |
Negative |
DPPCS |
DPPX Ab CBA, S |
CBA |
Negative |
DPPTS |
DPPX Ab IFA Titer, S |
IFA |
<1:240 |
GABIS |
GABA-B-R Ab IF Titer Assay, S |
IFA |
<1:120 |
GFACS |
GFAP CBA, S |
CBA |
Negative |
GFATS |
GFAP IFA Titer, S |
IFA |
<1:240 |
IG5CS |
IgLON5 CBA, S |
CBA |
Negative |
IG5TS |
IgLON5 IFA Titer, S |
IFA |
<1:240 |
GL1CS |
mGluR1 Ab CBA, S |
CBA |
Negative |
GL1TS |
mGluR1 Ab IFA Titer, S |
IFA |
<1:240 |
NFHCS |
NIF Heavy Chain CBA, S |
CBA |
Negative |
NIFTS |
NIF IFA Titer, S |
IFA |
<1:240 |
NFLCS |
NIF Light Chain CBA, S |
CBA |
Negative |
NMDIS |
NMDA-R Ab IF Titer Assay, S |
IFA |
<1:120 |
PC1BS |
PCA-1 Immunoblot, S |
IB |
Negative |
PCTBS |
PCA-Tr Immunoblot, S |
IB |
Negative |
Neuron-restricted patterns of IgG staining that do not fulfill criteria for ANNA-1, ANNA-2, CRMP-5-IgG, PCA-1, PCA-2, or PCA-Tr may be reported as "unclassified anti-neuronal IgG." Complex patterns that include nonneuronal elements may be reported as "uninterpretable."
Note: CRMP-5 titers lower than 1:240 are detectable by recombinant CRMP-5 Western blot analysis. CRMP-5 Western blot analysis will be done on request on stored serum (held 4 weeks). This supplemental testing is recommended in cases of chorea, vision loss, cranial neuropathy, and myelopathy. Call the Neuroimmunology Laboratory at 800-533-1710 to request CRMP-5 Western blot.
Day(s) and Time(s) Performed
AGN1S, AMPHS, AMPIS, ANN1S, ANN2S, ANN3S, CRMS, DPPIS, DPPTS, GABIS, GFAIS, GFATS, GL1IS, GL1TS, IG5IS, IG5TS, NIFIS, NIFTS, NMDIS, PCAB2, PCABP, PCATR:
Monday through Friday; 5 a.m., 7 a.m., 5 p.m.
Saturday, Sunday; 6 a.m.
AMPCS, CS2CS, DDPCS, GABCS, LG1CS, NMDCS:
Monday through Friday; 10 p.m.
Sunday; 10 p.m.
GL1CS, IG5CS:
Monday, Thursday; 6 p.m.
AINCS, NFHCS, NFLCS:
Tuesday, Thursday; 6 p.m.
GFACS:
Monday, Wednesday, Friday; 6 p.m.
CRMWS:
Monday through Thursday; 8 a.m.
AGNBS, AMIBS, AN1BS, AN2BS, PC1BS, PCTBS:
Monday through Friday; 6 p.m.
ARMO:
Monday through Thursday; 1 p.m.
Saturday; 8 a.m.
GD65S:
Monday through Friday; 5 a.m., 2 p.m.
Saturday, Sunday; 7 a.m.
ARBI, CCN, CCPQ, GANG:
Monday through Friday; 6 a.m., 8 a.m., 6 p.m.
Saturday, Sunday; 7 a.m.
Performing Laboratory

Test Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.CPT Code Information
83519 x 3
86255 x 19
86341 x 1
83519 ARBI (if appropriate)
83519 ARMO (if appropriate)
84182 AGNBS (if appropriate)
86255 AINCS (if appropriate)
86256 AMPIS (if appropriate)
84182 AMIBS (if appropriate)
84182 AN1BS (if appropriate)
84182 AN2BS (if appropriate)
84182 CRMWS (if appropriate)
86255 DPPCS (if appropriate)
86256 DPPTS (if appropriate)
86256 GABIS (if appropriate)
86255 GFACS (if appropriate)
86256 GFATS (if appropriate)
86255 IG5CS (if appropriate)
86256 IG5TS (if appropriate)
86255 GL1CS (if appropriate)
86256 GL1TS (if appropriate)
86255 NFHCS (if appropriate)
86256 NIFTS (if appropriate)
86255 NFLCS (if appropriate)
86256 NMDIS (if appropriate)
84182 PC1BS (if appropriate)
84182 PCTBS (if appropriate)
LOINC Code Information
Test ID | Test Order Name | Order LOINC Value |
---|---|---|
ENS2 | Encephalopathy-Autoimmune Eval, S | 94697-0 |
Result ID | Test Result Name | Result LOINC Value |
---|---|---|
61516 | NMDA-R Ab CBA, S | 93503-1 |
61518 | AMPA-R Ab CBA, S | 93489-3 |
61519 | GABA-B-R Ab CBA, S | 93428-1 |
34257 | Encephalopathy, Interpretation, S | 69048-7 |
64279 | LGI1-IgG CBA, S | 94287-0 |
64281 | CASPR2-IgG CBA, S | 94285-4 |
64930 | DPPX Ab IFA, S | 82976-2 |
64928 | mGluR1 Ab IFA, S | 94347-2 |
605155 | GFAP IFA, S | 94346-4 |
606946 | IgLON5 IFA, S | 96476-7 |
606964 | NIF IFA, S | 96486-6 |
80776 | ANNA-2, S | 94343-1 |
83137 | ANNA-3, S | 94344-9 |
81184 | N-Type Calcium Channel Ab | 94348-0 |
81185 | P/Q-Type Calcium Channel Ab | 94349-8 |
83077 | CRMP-5-IgG, S | 94815-8 |
84321 | AChR Ganglionic Neuronal Ab, S | 94694-7 |
81596 | GAD65 Ab Assay, S | 94345-6 |
83138 | PCA-2, S | 94351-4 |
9477 | PCA-1, S | 94350-6 |
83076 | PCA-Tr, S | 94352-2 |
89080 | AGNA-1, S | 94341-5 |
81722 | Amphiphysin Ab, S | 94340-7 |
80150 | ANNA-1, S | 94342-3 |
36349 | Reflex Added | 77202-0 |