Head trauma is a common injury in emergency department. Investigation to search for complication is guided by the clinical examination and the case history, such as taking anti-thrombotics. Cranial computed tomography (CCT) is the gold standard to investigate, and is mandatory in case of antithrombotic drugs.

Recently, some biomarkers have proven their utility to rule-out mild head trauma without CCT in the general population. Among these biomarkers, S100β protein has been added in guidelines for mild head trauma. Some studies have found similar data in population taking anticoagulant or antiplatelet drugs.

The investigators aim to prove medical utility of S100β protein in population under antithrombotics, by the reduction of CCT use. Then, The investigators hypothesize that the add of S100β protein reduces cost of health care in the management of head injury in that population.

Inclusion Criteria:

• Patient ≥ 18 years old
• Taking antithrombotic medication (antiplatelet drugs, K vitamin antagonist, direct oral anticoagulants, heparins)
• Mild head trauma with Glasgow coma scale ≥ 13
• Trauma occured ≤ 6 hours
• Agreeing the participation in the study

Exclusion Criteria:

• Head injury occured > 6 hours
• Patient < 18 years old or under juridic protection
• pregnant women
• polytrauma
• Glasgow coma scale ≤ 12
• ancient or actual cerebral ou cutaneous neoplasia

Patient taking antithrombotic medication with mild head trauma and trauma occured ≤ 6 hours