High serum S100B levels for trauma patients without head injuries

OBJECTIVE: Studies of patients with head trauma have demonstrated a correla tion between a serum marker of brain tissue damage, namely S100B, and neuro radiological findings. It was recently demonstrated that the increases in s erum S100B levels after heart surgery have extracerebral origins, probably surgically traumatized fat, muscle, and bone marrow. The current study exam ined multiltrauma patients without head trauma, to determine whether soft-t issue and bone damage might confound the interpretation of elevated serum S 100B concentrations for patients after head trauma. METHODS: A commercial assay was used to determine serum S100B concentration s for a normal population (n = 459) and multitrauma patients without head i njury (n = 17). Concentrations of the two subtypes of S100B (S100A1B and S1 00BB) were determined using separate noncommercial assays. RESULTS: The mean serum S100B concentration for a normal healthy population was 0.032 mug/L (median, 0.010 mug/L; standard deviation, 0.040 mug/L). Th e upper 97.5% and 95% reference limits were 0.13 and 0.10 mug/L, respective ly. No major age or sex differences were observed. Among trauma patients, s erum S100B levels were highest after bone fractures (range, 2-10 mug/L) and thoracic contusions without fractures (range, 0.5-4 mug/L). Burns (range, 0.8-5 mug/L) and minor bruises;also produced increased S100B levels. S100A1 B and S100BB were detected in all samples. CONCLUSION: Trauma, even in the absence of head trauma, results in high ser um concentrations of S100B. Interpretation of elevated S100B concentrations immediately after multitrauma may be difficult because of extracerebral co ntributions. S100B may have a negative predictive value to exclude brain ti ssue damage after trauma. Similarly, nonacute S100B measurements may be of greater prognostic value than acute measurements.