Specimen Requirements

Minimum Specimen Requirements

Stability

Days Performed

Sun - Sat

Turnaround Time

9 - 12 days

Methodology

Special Info

Reflex Algorithm: Each reflex test performed incurs additional charge. If immunofluorescence (IFA) patterns suggest CRMP-5-IgG, then CRMP-5-IgG Western blot is performed. If IFA patterns suggest amphiphysin antibody, then amphiphysin immunoblot is performed. If IFA pattern suggests AGNA-1 antibody, then AGNA-1 immunoblot is performed. If IFA pattern suggests ANNA-1 antibody, then ANNA-1 immunoblot is performed. If IFA pattern suggests ANNA-2 antibody, then ANNA-2 immunoblot is performed. If IFA pattern suggests PCA-1 antibody, then PCA-1 immunoblot is performed. If IFA pattern suggests PCA-Tr antibody, then PCA-Tr immunoblot is performed. If IFA pattern suggests IgLON5 antibody, then IgLON5 IFA titer IgLON5 cell-binding assay (CBA) is performed. If IFA pattern suggests AMPA-receptor antibody, and AMPA-receptor antibody CBA is positive, then AMPA-receptor antibody IFA titer assay is performed. If IFA pattern suggests GABA-B-receptor antibody, and GABA-B-receptor antibody CBA is positive, then GABA-B-receptor antibody IFA titer assay is performed. If IFA pattern suggests GFAP antibody, then GFAP IFA titer and GFAP CBA are performed. If IFA pattern suggests NMDA-receptor antibody, and NMDA-receptor antibody CBA is positive, then NMDA-receptor antibody IFA titer assay is performed. If IFA pattern suggests DPPX antibody, then DPPX antibody CBA and DPPX titer are performed. If IFA pattern suggests mGluR1 antibody, then mGluR1 antibody CBA and mGluR1 titer are performed. If IFA pattern suggests NIF antibody, then alpha internexin CBA, NIF heavy chain CBA, NIF light chain CBA, and NIF titer are performed. Neuron-restricted patterns of IgG staining that do not fulfill criteria for ANNA-1, ANNA-2, ANNA-3, 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." Relevant clinical information, ordering provider name, phone number, mailing address, and e-mail address are required. Grossly hemolyzed, lipemic or icteric specimens will be rejected.

Clinical Info

Aids in 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 spinal fluid specimens. A diagnosis of autoimmune encephalopathy should be suspected on the basis of clinical course, coexisting autoimmune disorder (eg, thyroiditis, diabetes), serological evidence of autoimmunity, spinal fluid evidence of intrathecal inflammation, neuroimaging or electroencephalographic abnormalities, and favorable response to trial of immunotherapy. Detection of one or more neural autoantibodies aids the diagnosis of autoimmune encephalopathy and may guide a search for cancer. Importantly, autoimmune encephalopathies are reversible. Misdiagnosis as a progressive (currently irreversible) neurodegenerative condition is not uncommon and has devastating consequences for the patient. Clinicians must consider the possibility of an autoimmune etiology in the differential diagnoses of encephalopathy.