Clinical Utility of the Protein S100B to Evaluate Traumatic Brain Injury in the Presence of Acute Alcohol Intoxication

Objective: To examine the role of the protein S100B as a biomarker for traumatic brain injury (TBI) in the presence of acute alcohol intoxication. Participants: A total of 159 patients who presented to a large urban level 1 trauma center in Vancouver, British Columbia, Canada, were included. Patients were classified into 4 clinical groups-medical controls (MC), trauma controls (TC), uncomplicated mild TBI (MTBI), and definite TBI (DTBI)-and 2 day-of-injury alcohol intoxication groups (ie, sober and intoxicated). Procedure: Blood samples were collected within 8 hours of injury. Main Outcome Measure: Protein S100B concentration (mu g/L; Sangtec 100 Elisa, DiaSorin, Stillwater, Minnesota). Results: Higher S100B levels were found in patients who sustained a TBI than in those in the MC and TC groups (DTBI & MTBI>TC & MC). There was a positive linear relation between S100B levels and brain injury severity (DTBI>MTBI). Alcohol consumption at the time of injury did not generally affect S100B levels. The S100B levels had medium diagnostic accuracy for the majority of patients, with the exception of the DTBI-sober group in which S100B levels had very high diagnostic accuracy. Conclusion: Patients with uncomplicated MTBIs and DTBIs had much higher levels of S100B than MC and TC participants. This biomarker had medium diagnostic accuracy for detecting DTBI in the presence of alcohol intoxication and very high accuracy in sober patients.