The Reference Level of Serum S-100B Protein for Poor Prognosis in Patients with Intracranial Extracerebral Hematoma

BACKGROUND S-100B protein, blood-brain barrier permeability marker, is one of a few biochemical indicators useful in the evaluation of traumatic brain injury. Our aim was to correlate serum concentration of S-100B with clinical condition and CT head scan findings as well as to estimate the level of the protein significant for clinical outcome prediction. METHODS The cohort of 41 subjects underwent clinical examination by the neurosurgeon, consciousness was evaluated with Glasgow Coma Scale (GCS). Diagnosis was established on the basis of CT head scans. Venous blood samples were collected before surgery. Serum concentration of S-100B protein was estimated using electrochemiluminesce immunoassays (ECLIA) on Cobas 6000 Analyzer (Roche Diagnostics). Clinical outcome was measured applying Glasgow Outcome Scale (GOS). Finally, data were analyzed with Statistica, v. 8.0 (StatSoft, Inc. 2007). RESULTS The average S-100B concentration was 0.95 ± 1.75 μg/L. Statistical analysis revealed significant correlation between S-100B and GCS, GOS and dimers-D concentration (p<0.001, Spearman correlation test). There were statistically significant differences in the S-100B concentration depending on the presence of brain oedema (1.29±2.02 vs. 0.06±0.03; p<0.01, Mann-Whitney test) or contusion foci (1.37±1.77 vs. 0.72±1.92; p<0.01) in CT scans. The S-100B concentration of 0.288 μg/L was determined as a cut-off point for unfavorable clinical outcome prediction (ROC, p<0.001). CONCLUSIONS Association between serum S-100B concentration and clinical, radiological or laboratory findings prove its usefulness as a diagnostic marker for assessment of brain trauma severity. The concentration of the protein >0.288 μg/L is associated with poor prognosis.