Prolonged elevation of serum neurofilament light after concussion in male Australian football players

© 2021, The Author(s). Background: Biomarkers that can objectively guide the diagnosis of sports-related concussion, and consequent return-to-play decisions, are urgently needed. In this study, we aimed to determine the temporal profile and diagnostic ability of serum levels of neurofilament light (NfL), ubiquitin carboxy-terminal hydrolase L1 (UCHL1), glial fibrillary acidic protein (GFAP), and tau in concussed male and female Australian footballers. Methods: Blood was collected from 28 Australian rules footballers (20 males, 8 females) at 2-, 6-, and 13-days after a diagnosed concussion for comparison to their levels at baseline (i.e. pre-season), and with 27 control players (19 males, 8 females) without a diagnosis of concussion. Serum concentrations of protein markers associated with damage to neurons (UCHL1), axons (NfL, tau), and astrocytes (GFAP) were quantified using a Simoa HD-X Analyzer. Biomarker levels for concussed players were compared over time and between sex using generalised linear mixed effect models, and diagnostic performance was assessed using area under the receiver operating characteristic curve (AUROC) analysis. Results: Serum NfL was increased from baseline in male footballers at 6- and 13-days post-concussion. GFAP and tau were increased in male footballers with concussion at 2- and 13-days respectively. NfL concentrations discriminated between concussed and non-concussed male footballers at all time-points (AUROC: 2d = 0.73, 6d = 0.85, 13d = 0.79), with tau also demonstrating utility at 13d (AUROC = 0.72). No biomarker differences were observed in female footballers after concussion. Conclusions: Serum NfL may be a useful biomarker for the acute and sub-acute diagnosis of concussion in males, and could inform neurobiological recovery and return-to-play decisions. Future adequately powered studies are still needed to investigate biomarker changes in concussed females.