Glial Fibrillary Acidic Protein (GFAP) and Ubiquitin Carboxy-terminal Hydrolase L1 (UCH-L1) to Exclude Lesions Linked to Significant Traumatic Brain Injuries

The goal of this observational study is to evaluate the performance of UCH-L1 and GFAP combined in patients with a mild traumatic brain injury. The main question :

• Does the combination of UCH-L1 and GFAP can exclude brain injuries detected with CT scan in the first twelve hours after a mild traumatic brain injury?

Participants will do the exams planed in routine care and :

* during the expected blood sampling an additional blood sample will be done,
* seven days after the discharge a call will be done by the investigator.

Main study

The main study includes subjects presenting to the emergency department within 12 hours of mild traumatic brain injury with an intermediate risk of clinical worsening or intracranial lesions.

The participants have at least one of the following characteristics, as defined in the French recommendations

* \> 65 years treated with anti-platelet agents
* Glasgow Score \< 15 at two hours after the trauma if associated intoxication (alcohol, narcotic, psychotropic)
* Trauma with high kinetics (for information only: a risk mechanism (pedestrian knocked down by a motorized vehicle, ejection from a vehicle, fall from more than 3 steps (more than one meter), etc.),
* Amnesia of facts \> 30 min before the trauma

The study includes clinical sites in France and Monaco. Participants have a blood sample and a brain scan as part of the care. The participation of subjects in the study will not influence their treatment.

Ancillary study The ancillary study uses qualitative research methodology to assess acceptance by physicians and patients of a biological test rather than a CT scan to exclude intracranial complication after mild traumatic brain injury.

The study will takes place in the emergency department of the Nice University Hospital Center (CHU of Nice). It will include 30 subjects: 15 subjects presenting to the emergency room for mild traumatic brain injury and included in the main protocol and 15 prescribing emergency physicians.

The participation of subjects in the study will not influence their treatment.

Eligibility Criteria:
Inclusion Criteria:

* Traumatic brain injury defined by

  * Impact on the skull or the face AND OR
  * Acceleration / deceleration
* Glasgow Coma Scal 13, 14 or 15
* One of the following 4 criteria:

  * \> 65 years treated with anti-platelet agent,
  * GCS \< 15 two hours after the trauma if associated intoxication (alcohol, narcotic, psychotropic),
  * Trauma with high kinetics (for information only: a risk mechanism (pedestrian knocked down by a motorized vehicle, ejection from a vehicle, fall from more than 3 steps (more than one meter), etc.),
  * Amnesia of facts \> 30 min before the trauma.
* Having a blood sample taken as part of care with a delay between the clinical event and the biological sample \< 12 hours
* Having a CT-scan prescription as part of the MTBI evaluation
* Patient who signed an informed consent form

Exclusion Criteria:

* Person not affiliated or not benefiting from a health insurance scheme.
* Person under judicial protection.
* Person with restrictions of freedom or subject to Articles L.3212-1 and L.3213-1, and not included in Article L.1122-8 of the French CSP
* Blood collection time \> 12 hours
* Subjects for which a scan would be carried out systematically, including:

  * GCS \<13 (moderate or severe trauma),
  * congenital hemostasis disorders or patient on anti-coagulant treatment,
  * clinical signs evoking a fracture of the vault or the base of the skull,
  * more than one episode of vomiting,
  * post-traumatic convulsion,
  * focal neurological deficit.
* Obstacle to follow-up at D7
* Malignant melanomas