biostudies-literaturevan Pamelen JDutch National MS Foundation20552173251370830https://www.ebi.ac.uk/biostudies/studies/S-EPMC12405697biostudies-literatureUnknown11(3)<h4>Background</h4>In relapsing-remitting multiple sclerosis (RRMS), the assessment of clinical disease activity can be challenging.<h4>Objectives</h4>To determine the diagnostic potential of serum neurofilament light (sNfL) and glial fibrillary acidic protein (sGFAP) to distinguish a relapse from other causes of deterioration.<h4>Methods</h4>In this multicenter, prospective study, RRMS patients with new neurological symptoms in the last 14 days were followed for 12 weeks. A diagnosis was established by the treating physician or, when in doubt, a panel of experienced neurologists. Blood samples were taken at baseline and week 12.<h4>Results</h4>A total of 65 patients were included. At baseline, patients with a clear relapse had a significantly higher median sNfL (14.6 pg/mL) than those witMultiple sclerosis journal - experimental, translational and clinicalRelapse or no relapse in multiple sclerosis: Can disease activity biomarkers support the clinician?PMC12405697OZ2018-007Arnoldus EPJKillestein JLissenberg BIvan Pamelen Jvan Vliet JKoel-Simmelink MJAVisser LHTeunissen CEde Beukelaar JfalseRelapse or no relapse in multiple sclerosis: Can disease activity biomarkers support the clinician?<h4>Background</h4>In relapsing-remitting multiple sclerosis (RRMS), the assessment of clinical disease activity can be challenging.<h4>Objectives</h4>To determine the diagnostic potential of serum neurofilament light (sNfL) and glial fibrillary acidic protein (sGFAP) to distinguish a relapse from other causes of deterioration.<h4>Methods</h4>In this multicenter, prospective study, RRMS patients with new neurological symptoms in the last 14 days were followed for 12 weeks. A diagnosis was established by the treating physician or, when in doubt, a panel of experienced neurologists. Blood samples were taken at baseline and week 12.<h4>Results</h4>A total of 65 patients were included. At baseline, patients with a clear relapse had a significantly higher median sNfL (14.6 pg/mL) than those wit2025-01-01T00:00:00Z2025 Jul-Sep2026-05-29T22:02:41.743Z2026-04-08T06:13:29.044ZS-EPMC124056974090976010.1177/20552173251370830