15 of these had a CT scan, 20 were admitted and 9 patients had both a CT and admission. All of these patients had normal CT findings and/or normal follow-up. Under-triage (not performing a CT when recommended) occurred in 28 patients (7%) with elevated S100B levels. None of these patients had any significant intracranial complications on follow-up. S100B

displayed a sensitivity and NPV of 100% for significant intracranial complications, a specificity of 28% and a positive predictive value (PPV) of 6%, see Table ​Table22. Table 2 Cross tabulation showing statistical values for S100B Inhibitors,research,lifescience,medical and significant intracranial complications Discussion The first report concerning serum S100B as a possible biomarker in MHI was published in 1995

[15]. Since then, numerous reports and a meta-analysis, documenting the potential of S100B to safely reduce CT scans following MHI, have increased the evidence for clinical use [20-24]. However, actual clinical validation has never been reported despite the biomarker being used clinically in several Inhibitors,research,lifescience,medical European countries. In 2007, S100B was introduced as a clinical tool in the management of MHI in our hospital, in an attempt to reduce CT scans after these injuries. This study shows that this implementation has been successful and that S100B, using a cut-off of less than 0.10 μg/L for normal values and a time window of 3 hours from injury, shows similar predictive Inhibitors,research,lifescience,medical values to the derivation studies. Low compliance

to guidelines is a common problem [5]. 32% of patients with normal Inhibitors,research,lifescience,medical S100B levels were over-triaged with CT, admission or both. None of these had any intracranial complications. It is natural to expect caution when using new routines, especially concerning an injury where biomarkers have never been used before. Also, physicians must always be free to exert clinical judgement since management guidelines are merely an aid in the clinical process. Some patients cannot be sent home from the ED irrespective of S100B and/or CT findings (for example; elderly patients without support in their home environment, serious intoxication and patients Inhibitors,research,lifescience,medical with other Cilengitide injuries). Our adapted guidelines are based upon the evidence-based SNC management guidelines from the year 2000 [1]. Since this publication, considerable new evidence has emerged in this field, including validated guidelines based upon patient history and clinical examination [7-9]. The impact of including S100B in other guidelines is unknown. However, the SNC guidelines have proved accurate in comparison studies [8,10] so the implementation of S100B into these is justifiable. Despite this, the examination of S100B within other guidelines is naturally warranted. Owing to the predictive properties of S100B, the biomarker is best adapted into an intermediate risk group of patients, such as in this study. The prevalence of traumatic intracranial injury in this group was 4.7%, similar to other cohorts.