Traumatic Brain Injury

sec_arr Appendix D: TBI Biomarkers - Protein S100B Testing

TBI Biomarkers: Protein S100B Testing

Serum S100B protein levels have been used successfully as a screening, monitoring, and prediction tool in patients with suspected TBI most often as part of a clinical decision tool on the need to perform head computerized tomography in the acute setting.1 S100B current utility is in screening out the need for imaging in children to reduce radiation exposure in the developing brain – not predicting functional outcomes. The limitations of biomarkers in mild TBI have recently been reviewed,2 including the low specificity of blood biomarkers (including S100B) in brain injury and the difficulty of predicting mTBI outcomes in general, regardless of the initial clinical evaluation. A 2014 review of the utility of S100B for sport-related concussion was unable to define a single S100B cutoff level (0.1 μg/L) to rule in or rule out concussion.4 Based on the low clinical utility (beyond the initial acute evaluation on whether to image) and the limited-to-no predictive value for functional outcomes, the Task Group’s consensus is that S100B testing should not be used as a single test to diagnosis mTBI and/or clear a LEO to return-to-work.


  1. Thelein EP, Nelson DW, Bellander BM. A review of the clinical utility of serum S100B protein levels in the assessment of traumatic brain injury. Acta Neurochir. 2017;159:209–225.
  2. Hier DB, Obafemi-Ajayi T, Thimgan MS, et al. Blood biomarkers for mild traumatic brain injury: a selective review of unresolved issues. Biomarker Research. 2021:9;70.
  3. Lumba-Brown A, Yeates KO, Sarmiento K, et al. Centers for Disease Control and Prevention Guideline on the Diagnosis and Management of Mild Traumatic Brain Injury Among Children JAMA Pediatr. 2018;172:e182853.
  4. Schulte S, Podlog LW, Hamson-Utley JJ, et al. A systematic review of the biomarker S100B: implications for sport-related concussion management J Athl Train. 2014;49:830-50.