Autoantibodies are crucial for diagnosing central nervous system (CNS) autoimmune disorders. In autoimmune astrocytopathy, autoantibodies targeting astrocytes, such as those against glial fibrillary acidic protein (GFAP) or aquaporin protein 4 (AQP4), serve as indispensable diagnostic markers. Nevertheless, the diagnostic process remains challenging for patients who exhibit astrocytic reactivity on immunological tests but lack detectable specific autoantibodies