Objective to investigate plasma S100b concentration following competitive play and concussive episodes; to compare plasma S100b concentration in professional rugby players with age matched non-contact athletic controls; to develop an objective blood biomarker to aid in the diagnosis of concussion.

Design Prospective case-control study

Setting Professional rugby club, Elite rowing clubs.

Participants Professional rugby players (n=44); elite rowers (age/activity matched athletic controls) (n=16).

Interventions Blood samples were collected at baseline (14 days prior to training/competitive play) in both the rugby and rowing cohort. Rugby players were again assessed one hour following competitive games in the early, middle and late season (3 times). This was repeated again the following season (6 data sets). Concussed players were re-evaluated following concussion.

Outcomes Plasma was prepared and assessed for S100b concentration by ELISA (Abnova). Metabolomic profiling of samples was carried out by two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC×GC-TOFMS).

Main results There was significant increase in plasma S100b following competitive play, compared to baseline (p<0.001). Over 1000 metabolites were detected by GC×GC-TOFMS in a single sample run, covering a functionally wide range of small molecules. The post-match metabolic profile showed significant changes in several metabolites; these are at present being validated and analysed further.

Conclusions There is a significant effect of competitive play on circulating S100b. Data on metabolomic profiles are being collected continually throughout the season and being clustered according to concussive and non-concussive episodes. It is hoped that this analysis may reveal concussion-specific changes in the metabolomic profile of players.

Competing interests None.