In the previous issue of Critical Care, Mondello and

colleagues [1] demonstrate that easy to obtain bio chemi cal markers of brain injury in peripheral blood may comple-ment current predictors of outcome in severe traumatic brain injury (TBI). Th e study also advocates that use of biomarkers may contribute to better understanding of the pathophysiological mechanisms of brain damage. After TBI, brain tissue-specifi c neuronal and glial proteins may suddenly appear in the systemic circulation via leakage through the disturbed blood brain barrier or via leakage to the cerebrospinal fl uid and subsequent normal transport to the circulation. Despite the strength of the association between existing predictors of out come, the prognostic value is still modest. Studies in more than 10,000 patients demonstrate a diagnostic accuracy of 0.70 to 0.84, which is insuffi cient as a diagnostic and prog