S100b immunoassay: an assessment of diagnostic utility in minor head trauma

J Emerg Med. 2011 Sep;41(3):285-93. doi: 10.1016/j.jemermed.2010.05.040. Epub 2010 Aug 8.

Abstract

Background: Over 1.4 million patients present annually to United States (US) emergency departments with minor head trauma. Many undergo unnecessary head computed tomography (HCT).

Objectives: We sought to determine the diagnostic accuracy of S100B, a central nervous system peptide, to screen for HCT+ head injury.

Methods: This study was a prospective observational study of adults with minor head trauma. Patients presenting within 6h of injury and undergoing HCT for evaluation were eligible. All HCTs were blindly reviewed for presence of a priori defined intracranial injury (HCT+). Quantitative S100B levels were determined by enzyme-linked immunosorbent assay.

Results: A total of 346 patients were enrolled over 12 months, mean age 48 years (± 23 years), 62% male. Twenty-two (6.4%) were HCT+. Vomiting, headache, anterograde amnesia, Glasgow Coma Scale score<15, nausea, and loss of consciousness were associated with HCT+ results. Median S100B levels were significantly elevated in HCT+ (115 ng/dL) vs. HCT- (56.0 ng/dL) patients (p=0.032). Receiver operator characteristic analysis demonstrated an area under the curve of 0.643. Sensitivity and specificity were 86% (95% confidence interval [CI] 67-96) and 37% (95% CI 29-45%) at 42 ng/dL, 91% (95% CI 72-98%) and 24% (95% CI 17-31%) at 32 ng/dL, and 96% (95% CI 78-100%) and 13% (95% CI 9-20%) at 24 ng/dL, respectively.

Conclusion: The study demonstrates that S100B may be a sensitive but non-specific marker of HCT+ injury.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Biomarkers / blood
  • Craniocerebral Trauma / blood
  • Craniocerebral Trauma / diagnosis*
  • Enzyme-Linked Immunosorbent Assay
  • Female
  • Head Injuries, Closed / blood
  • Head Injuries, Closed / diagnosis*
  • Humans
  • Male
  • Middle Aged
  • Nerve Growth Factors / blood*
  • Prospective Studies
  • S100 Calcium Binding Protein beta Subunit
  • S100 Proteins / blood*
  • Sensitivity and Specificity
  • Young Adult

Substances

  • Biomarkers
  • Nerve Growth Factors
  • S100 Calcium Binding Protein beta Subunit
  • S100 Proteins
  • S100B protein, human