TBI patients with syndecan-1 ≥ 40 ng/ml (EoT+) had physiological derangements shortly after injury and were more likely to have lower arrival systolic blood pressure, higher heart rate and base deficit, altered rTEG parameters compatible with coagulopathy (lower MA and prolonged ACT) and increased sympathoadrenal activation. This evidence concerns the gene SDC1 and blood coagulation disease.