(a) Comparison of the range of sensitivities (based on neuromyelitis optica [NMO] patients) and accuracy of assays used to identify aquaporin-4 antibodies in serum of NMO patients (accuracy = [sensitivity × specificity] / 100). The specificities, listed on the right hand side, are based on multiple sclerosis (MS) patients. (b) The sensitivity (±95% confidence interval) and specificity of indirect immunofluorescence (IIF) assays published. Assays marked by red dots were carried out at an individual center, suggesting that cohort selection might influence sensitivity. CBA, cell-based assay; ELISA, enzyme-linked immunosorbent assay; FACS, flow cytometry; FIPA, fluorescence immunoprecipitation assay; RIPA, radioimmunoprecipitation assay.