title: Subject-specific increases in serum S-100B distinguish sports-related concussion from sports-related exertion.
abstract: BACKGROUND
  The on-field diagnosis of sports-related concussion (SRC) is complicated by the lack of an accurate and objective marker of brain injury.
  
  
  OBJECTIVE
  To compare subject-specific changes in the astroglial protein, S100B, before and after SRC among collegiate and semi-professional contact sport athletes, and compare these changes to differences in S100B before and after non-contact exertion.
  
  
  METHODS
  Longitudinal cohort study.
  
  
  METHODS
  From 2009-2011, we performed a prospective study of athletes from Munich, Germany, and Rochester, New York, USA. Serum S100B was measured in all SRC athletes at pre-season baseline, within 3 hours of injury, and at days 2, 3 and 7 post-SRC. Among a subset of athletes, S100B was measured after non-contact exertion but before injury. All samples were collected identically and analyzed using an automated electrochemiluminescent assay to quantify serum S100B levels.
  
  
  RESULTS
  Forty-six athletes (30 Munich, 16 Rochester) underwent baseline testing. Thirty underwent additional post-exertion S100B testing. Twenty-two athletes (16 Rochester, 6 Munich) sustained a SRC, and 17 had S100B testing within 3 hours post-injury. The mean 3-hour post-SRC S100B was significantly higher than pre-season baseline (0.099±0.008 µg/L vs. 0.058±0.006 µg/L, p = 0.0002). Mean post-exertion S100B was not significantly different than the preseason baseline. S100B levels at post-injury days 2, 3 and 7 were significantly lower than the 3-hour level, and not different than baseline. Both the absolute change and proportional increase in S100B 3-hour post-injury were accurate discriminators of SRC from non-contact exertion without SRC (AUC 0.772 and 0.904, respectively). A 3-hour post-concussion S100B >0.122 µg/L and a proportional S100B increase of >45.9% over baseline were both 96.7% specific for SRC.
  
  
  CONCLUSIONS
  Relative and absolute increases in serum S100B can accurately distinguish SRC from sports-related exertion, and may be a useful adjunct to the diagnosis of SRC.
authors.affiliation: Department of Trauma Surgery, Klinikum der Universität München, Ludwig-Maximilians Universität, München, Germany.
authors.forename: Karin
authors.initials: K
authors.lastname: Kiechle
authors.affiliation: Department of Emergency Medicine, University of Rochester Medical Center, Rochester, New York, United States of America.
authors.forename: Jeffrey J
authors.initials: JJ
authors.lastname: Bazarian
authors.affiliation: Department of Emergency Medicine, University of Rochester Medical Center, Rochester, New York, United States of America.
authors.forename: Kian
authors.initials: K
authors.lastname: Merchant-Borna
authors.affiliation: Department of Neurosurgery, Klinikum der Universität München, Ludwig-Maximilians Universität, München, Germany.
authors.forename: Veit
authors.initials: V
authors.lastname: Stoecklein
authors.affiliation: Department of Athletics and Recreation, University of Rochester, Rochester, New York, United States of America.
authors.forename: Eric
authors.initials: E
authors.lastname: Rozen
authors.affiliation: Department of Emergency Medicine, University of Rochester Medical Center, Rochester, New York, United States of America.
authors.forename: Brian
authors.initials: B
authors.lastname: Blyth
authors.affiliation: Department of Neurosurgery, University of Rochester Medical Center, Rochester, New York, United States of America.
authors.forename: Jason H
authors.initials: JH
authors.lastname: Huang
authors.affiliation: Department of Neurosurgery, University of Rochester Medical Center, Rochester, New York, United States of America.
authors.forename: Samantha
authors.initials: S
authors.lastname: Dayawansa
authors.affiliation: Department of Trauma Surgery, Klinikum der Universität München, Ludwig-Maximilians Universität, München, Germany.
authors.forename: Karl
authors.initials: K
authors.lastname: Kanz
authors.affiliation: Department of Trauma Surgery, Technical University of Munich, München, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Biberthaler
mesh_terms: D000328:Adult; D056352:Athletes; D015415:Biomarkers / Q000097:blood; D001924:Brain Concussion / Q000097:blood* / Q000175:diagnosis / Q000235:genetics; D005260:Female; D015870:Gene Expression; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D005082:Physical Exertion / Q000235:genetics*; D064568:S100 Calcium Binding Protein beta Subunit / Q000097:blood* / Q000235:genetics; D013177:Sports; D013997:Time Factors
chemical_list: D015415:Biomarkers; D064568:S100 Calcium Binding Protein beta Subunit; C579160:S100B protein, human