Test Details: Neuromyelitis optica spectrum disorders (NMOSD) are rare relapsing autoimmune disorders that cause inflammation specifically in the optic nerve and spinal cord. Aquaporin-4 receptor (AQP4) and myelin oligodendrocyte glycoprotein (MOG) antibody testing is used for diagnosis and evaluation of neuromyelitis optica (NMO), acute myelitis, spinal cord lesions, autoimmune encephalitis or NMOSD. This test is useful in the initial evaluation of neuromyelitis optica (NMO) spectrum disorders. This test uses a cell-based assay (CBA) to detect antibodies against aquaporin-4, diagnosis of autoimmune AQP4 channelopathy, diagnosis of neuromyelitis optica (NMO), distinguishing NMOSD from multiple sclerosis early in the course of disease.