RESUMEN
BACKGROUND: The incidence of concussion in professional direct-contact sports, particularly in rugby, has increased in recent years. To date, cognitive assessment is the most common means of determining whether a concussed player can return to the game. Serum S100B assay, an objective blood test known to be useful in brain injury management, may offer a novel additional approach to the management of concussed male rugby players. OBJECTIVE: The aim of this study was to investigate the S100B utility for the determination of concussion in a professional 15-players-a-side rugby team. METHODS: Thirty-nine male rugby players were included in a prospective study during the 2014-2015 French championship season. Serum sampling was carried out several times at baseline and after a match and/or a concussion, at set times (2, 36 h). Serum S100B concentrations were determined using chemiluminescence immunoassay on a Roche Diagnostics® instrument. RESULTS: The players' basal serum S100B was stable during the season and was not correlated with anthropometric data, body composition, or creatine kinase concentration. A significant increase in S100B concentration within 2 h after a game (without concussion) was observed. This increase was correlated with the number of body collisions during a match. Seventy-seven assays were performed 36 h after a game, including the follow-up of five concussed players. Thirty-six hours after a match, an increase of a minimum of 20 % compared with individual basal concentrations identified concussion with 100 % sensitivity and 81 % specificity. CONCLUSION: S100B measured 36 h after a match is thus a discriminating test to identify concussion in a male rugby player, with a 100 % negative predictive value.