Exclusion of alternative diagnoses: A component of the 2023 MOGAD criteria that belongs at the forefront, not in the background.

A recent study evaluating the diagnostic performance of the 2023 MOGAD criteria found that it had relatively low specificity. However, this study did not apply the component of these criteria that requires exclusion of alternative diagnoses (item C) when evaluating its performance, raising questions surrounding the relevance of the study's findings to the use of these criteria in routine practice. This correspondence acknowledges the challenge of clinically applying this component of diagnostic criteria, discusses what exclusion of alterative diagnoses actually entails conceptually, and emphasizes the importance of its inclusion in future studies aimed at evaluating the performance of proposed criteria.