S100-B protein as a screening tool for the early assessment of minor head injury

Ann Emerg Med. 2012 Mar;59(3):209-18. doi: 10.1016/j.annemergmed.2011.07.027. Epub 2011 Sep 23.


Study objective: A computed tomography (CT) scan has high sensitivity in detecting intracranial injury in patients with minor head injury but is costly, exposes patients to high radiation doses, and reveals clinically relevant lesions in less than 10% of cases. We evaluate S100-B protein measurement as a screening tool in a large population of patients with minor head injury.

Methods: We conducted a prospective observational study in the emergency department of a teaching hospital (Bordeaux, France). Patients with minor head injury (2,128) were consecutively included from December 2007 to February 2009. CT scans and plasma S100-B levels were compared for 1,560 patients. The main outcome was to evaluate the diagnostic value of the S100-B test, focusing on the negative predictive value and the negative likelihood ratio.

Results: CT scan revealed intracranial lesions in 111 (7%) participants, and their median S100-B protein plasma level was 0.46 μg/L (interquartile range [IQR] 0.27 to 0.72) versus 0.22 μg/L (IQR 0.14 to 0.36) in the other 1,449 patients. With a cutoff of 0.12 μg/L, traumatic brain injuries on CT were identified with a sensitivity of 99.1% (95% confidence interval [CI] 95.0% to 100%), a specificity of 19.7% (95% CI 17.7% to 21.9%), a negative predictive value of 99.7% (95% CI 98.1% to 100%), a positive likelihood ratio of 1.24 (95% CI 1.20 to 1.28), and a negative likelihood ratio of 0.04 (95% CI 0.006 to 0.32).

Conclusion: Measurement of plasma S100-B on admission of patients with minor head injury is a promising screening tool that may be of help to support the clinician's decision not to perform CT imaging in certain cases of low-risk head injury.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Brain Injuries / diagnosis
  • Brain Injuries / diagnostic imaging
  • Craniocerebral Trauma / diagnosis*
  • Craniocerebral Trauma / diagnostic imaging
  • Emergency Service, Hospital
  • Female
  • Glasgow Coma Scale
  • Humans
  • Male
  • Middle Aged
  • Nerve Growth Factors / blood*
  • Predictive Value of Tests
  • Prospective Studies
  • S100 Calcium Binding Protein beta Subunit
  • S100 Proteins / blood*
  • Statistics, Nonparametric
  • Tomography, X-Ray Computed


  • Nerve Growth Factors
  • S100 Calcium Binding Protein beta Subunit
  • S100 Proteins