The practical uses of serum neurofilament light chain as a biomarker in multiple sclerosis

Neurofilament light chain (NfL) is the predominant intermediate filament within neurones and is readily detectable in the peripheral blood following neuroaxonal injury. Serum NfL (sNfL) has emerged as a valuable biomarker of neuroaxonal damage in multiple sclerosis (MS) and other neurological disorders, with some sNfL platforms granted breakthrough device designation by the food and drug administration. Thus, it is crucial for clinical neurologists to understand the anticipated uses and limitations of sNfL sampling prior to its implementation in clinical practice. In this article, we explain how sNfL could be used as a diagnostic, prognostic, predictive and monitoring biomarker for MS. We evaluate the extent to which sNfL could be used to guide treatment decisions and discuss factors affecting sNfL reliability, offering strategies to mitigate these. Additionally, we propose future directions for research to facilitate safe and effective clinical implementation of sNfL in future.