Massimo Filippi, MD, Vita-Salute San Raffaele University, Milan, Italy, discusses the results of a multicenter MAGNIMS study, investigating the efficacy of two variations of the McDonald diagnosis criteria for multiple sclerosis (MS) in diagnosing MS in a cohort of 800 patients with clinical isolated syndrome (CIS); tests conducted included magnetic resonance imaging (MRI) and cerebrospinal fluid (CSF) analysis. It was found that the newer variation (2017-2018) was more sensitive but a little less specific than the older variation (2010). However, the lower specificity should not result in a higher false-positive rate as MS mimicking conditions are ruled out before criteria application; the new criteria reduced the average time until diagnosis by 10 months. By reducing diagnosis time, the new McDonald criteria may improve outcomes for patients with MS. This interview took place during the European Academy of Neurology 2021 congress.