Test ID: ENS2    
Encephalopathy, Autoimmune Evaluation, Serum

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

If indirect immunofluorescence assay (IFA) (ANNA-1, ANNA-2, PCA-1, PCA-2) is indeterminate, then paraneoplastic autoantibody Western blot is performed at an additional charge.

If client requests or if 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 Western blot is performed at an additional charge.

If IFA pattern suggests AMPA-receptor antibody, and AMPA-receptor antibody cell-binding assay (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-R receptor antibody is positive, then GABA-B-R 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.

See Encephalopathy Autoimmune Evaluation Algorithm-Serum in Special Instructions.

• Encephalopathy Autoimmune Evaluation Algorithm-Serum

ANN1S, ANN2S, ANN3S, PCABP, PCAB2, PCATR, AMPHS, CRMS, AGN1S, DPPIS, DPPTS, GL1IS, GLITS, GFAIS, GFATS, AMPIS, GABIS, NMDIS: Indirect Immunofluorescence Assay (IFA)

AMPCS, GABCS, NMDCS, LG1CS, CS2CS, DPPCS, GL1CS, GFACS: Cell Binding Assay (CBA)

ABLOT, CRMWS, WBN; Western Blot (WB)

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

ARMO: Live Cell Assay (LCA)