OBJECTIVES: Antibodies against water channel protein aquaporin 4 (AQP4) in astrocytes play a role in the etiology and physiopathology of neuromyelitis optica (NMO); detection of this immunoglobulin in serum is highly suggestive of this diagnosis. There are several immunoassays to detect the antibody with different sensitivities and specificities. We conducted a meta-analysis to determine the overall diagnostic accuracy from these tests. METHODS: We conducted a systematic review in five different electronic databases: Pubmed, Embase, The Cochrane Library, Database of Abstracts of Reviews of Effect (DARE) and Lilacs. We included both case control and consecutive enrollment studies that evaluated the performance of the immunoassays in patients with suspected NMO in comparison with the 2006 Wingerchuk diagnostic criteria. Articles were assessed by two different reviewers, who also extracted data. RESULTS: