Serum neurofilament light chain (sNfL) is a promising novel biomarker under investigation in multiple sclerosis (MS). A convenient, predictive, and widely representative biomarker is lacking in MS, so sNfL has the potential to fill this gap. Mark Freedman, MSc, MD, CSPQ, FAAN, FRCPC, University of Ottawa & Ottawa Hospital Research Institute, Ottawa, Canada, discusses the possible uses of sNfL in MS management. Firstly, sNfL may provide a useful prognostic biomarker, as it has been associated with aggressive versus mild disease. Its ease also means it can monitor progression and treatment efficacy, and thus, is beginning to be assessed as an outcome measure in many MS clinical trials. Dr Freedman also discusses ongoing investigations into the feasibility of sNfL measurements using blood spot testing rather than a full blood draw. This interview took place during the ACTRIMS Forum 2021.