Is a Glasgow Coma Scale Score of 15 Normal?
Yes, a GCS score of 15 is considered normal and indicates full consciousness with no apparent neurological deficits. 1
Understanding GCS 15
A GCS score of 15 represents the maximum possible score on the Glasgow Coma Scale and indicates:
- Full consciousness with intact eye opening, verbal response, and motor function 1
- No apparent neurological deficits at the time of assessment 1
- A positive prognostic indicator in the context of head injury 1
The GCS 15 patient demonstrates normal eye opening (4 points), is fully oriented with coherent speech (5 points), and obeys commands appropriately (6 points), totaling the maximum 15 points. 2
Clinical Context in Traumatic Brain Injury
While GCS 15 is "normal," it does not exclude significant intracranial pathology in trauma patients:
- 3-14.8% of patients with GCS 15 have positive CT findings depending on the study population 3
- 0.2-0.6% require neurosurgical intervention despite presenting with GCS 15 4, 3
- Small contusions (<5 mm) are generally considered clinically unimportant in GCS 15 patients 1
In the largest prospective study of 1,899 patients with GCS 15 and head trauma, 282 (14.8%) had positive CT findings and 62 (3.2%) required craniotomy. 3
Risk Stratification for GCS 15 Patients
Not all GCS 15 patients are the same. The Canadian CT Head Rule identified high-risk factors that warrant CT imaging even with GCS 15: 3
- Failure to reach GCS 15 within 2 hours of injury
- Suspected open skull fracture
- Signs of basal skull fracture
- Vomiting more than once
- Age >64 years
Additional validated predictors of abnormal CT in GCS 15 patients include: 3
- Headache
- Drug or alcohol intoxication
- Deficits in short-term memory
- Physical evidence of trauma above the clavicle
- Seizure
- Loss of consciousness or amnesia
Warning Signs of Deterioration
Even with initial GCS 15, monitor for these red flags: 4
- Any decrease in GCS score (present in 82% of GCS 15 patients who required urgent craniotomy)
- New confusion (64% of urgent cases)
- Vomiting (36% of urgent cases)
- Restlessness (36% of urgent cases)
- Severe headache (45% of urgent cases)
Common Pitfalls
Do not equate GCS 15 with "no injury" - this is the most dangerous assumption. 5, 1 The American College of Emergency Physicians warns against discharging patients based solely on a "mild" GCS, particularly in elderly patients with confirmed intracranial hemorrhage. 5
Do not rely on GCS total score alone - the total score may not accurately reflect level of consciousness, as scores between 4-14 can represent multiple different states of consciousness. 6 Individual subscale behaviors provide more granular information. 6
Serial examinations are essential - a single GCS 15 assessment is a snapshot in time. 1 Patients can deteriorate hours after initial presentation, particularly within the first 4-6 hours. 3