How the Glasgow Coma Scale is calculated
GCS assesses level of consciousness across three components — eye opening, verbal response, and motor response — each scored independently and summed.
| Eye opening (1–4) | Verbal response (1–5) | Motor response (1–6) |
|---|---|---|
| 4 = Spontaneous 3 = To voice 2 = To pain 1 = None | 5 = Oriented 4 = Confused 3 = Inappropriate words 2 = Incomprehensible sounds 1 = None | 6 = Obeys commands 5 = Localises pain 4 = Withdraws from pain 3 = Abnormal flexion 2 = Extension 1 = None |
If the patient is intubated, verbal response can't be assessed — this is recorded as "T" (e.g. "9T") rather than assigning a numeric verbal score.
Normal values & severity
| Total GCS | Severity |
|---|---|
| 15 | Normal / fully alert |
| 13 – 15 | Mild traumatic brain injury |
| 9 – 12 | Moderate traumatic brain injury |
| 3 – 8 | Severe traumatic brain injury |
Clinical use
GCS is used to grade the severity of traumatic brain injury, track neurological trend over time, and trigger key decisions — most notably, a score of 8 or below is a widely used threshold for considering airway protection ("GCS ≤8, intubate"), because airway reflexes are often unreliable at this level. It's also used more broadly to describe consciousness in non-trauma settings (e.g. sepsis, overdose, metabolic encephalopathy). For children under 2 years, whose verbal responses can't be scored the same way, use the Pediatric GCS instead, which substitutes an age-appropriate verbal scale.
GCS vs AVPU
AVPU (Alert, Voice, Pain, Unresponsive) is a faster, coarser consciousness screen used when a full GCS isn't practical — e.g. rapid triage or a first-responder assessment before a detailed exam.
| GCS | AVPU | |
|---|---|---|
| Scale | 3–15 (13 possible totals) | 4 categories (A, V, P, U) |
| Components scored | Eye, verbal, motor — separately | Single overall responsiveness level |
| Speed | Slower — needs a structured exam | Faster — a quick bedside glance |
| Precision | Detects finer changes in trend over time | Coarser — better for rapid triage than serial monitoring |
| Rough equivalence | 15 | Alert |
| 13–14 | Voice | |
| 8–12 | Pain | |
| ≤7 | Unresponsive |
AVPU is a screening tool, not a replacement for GCS in trauma or ICU settings — once a patient needs closer monitoring, full GCS scoring gives a much more sensitive picture of neurological trend.
Frequently asked questions
What is the Glasgow Coma Scale?
A 3–15 point scale assessing level of consciousness across eye opening, verbal response, and motor response — used to grade traumatic brain injury severity and track neurological status over time.
What GCS score requires intubation?
A GCS of 8 or below is a widely used threshold for considering airway protection ("GCS ≤8, intubate"), since airway reflexes are often unreliable at this level — though the decision always depends on the full clinical picture.
What does a GCS of 15 mean?
15 is the maximum score, indicating a fully alert, oriented patient with normal eye, verbal, and motor responses.
How is GCS scored if a patient is intubated?
Verbal response can't be assessed in an intubated patient, so it's recorded as "T" (e.g. "9T") instead of a numeric verbal score, and the total isn't given a numeric severity category on verbal grounds alone.
What is the GCS score chart / GCS 3-15 chart?
It's the eye (1-4), verbal (1-5), and motor (1-6) scoring table above — each component scored to its own maximum, then summed for a total between 3 (deepest coma) and 15 (fully alert), with 13-15 graded mild, 9-12 moderate, and 3-8 severe.
Is GCS the same as AVPU?
No. AVPU (Alert, Voice, Pain, Unresponsive) is a faster 4-category screening tool, while GCS separately scores eye, verbal, and motor response on a 3-15 scale — GCS is more detailed and better suited to tracking neurological trend over time, while AVPU is faster for initial triage.
References
- Teasdale G, Jennett B. Assessment of coma and impaired consciousness: a practical scale. Lancet. 1974;2:81–84.
- Teasdale G, et al. The Glasgow Coma Scale at 40 years: standing the test of time. Lancet Neurol. 2014;13:844–854.