Neurofilament light chain and oligoclonal bands in the cerebrospinal fluid (CSF) of patients with radiologically isolated syndrome (RIS) are independent predictors of progression to clinically isolated syndrome (CIS) and multiple sclerosis (MS), a new study has shown. CSF samples from 75 patients with RIS were analysed for chitinase-3-like protein 1, neurofilament light chain and oligoclonal bands. High levels of neurofilament light chain (>619 ng/l) and the presence of oligoclonal bands in the CSF were each associated with shorter times to CIS and MS. The association with neurofilament light chain was more pronounced in patients with RIS aged ≥37 years. The findings highlight the importance of CSF analysis for determining the prognosis in patients with RIS.