The Glasgow Coma Scale: How to Score It Properly
Updated: 1 hour ago
The Glasgow Coma Scale, or GCS, is one of the most widely used tools in emergency care. It gives a structured, shared language for describing a patient's level of consciousness, and changes in the score can be one of the earliest signs that a patient is deteriorating. It looks simple on paper, but it is easy to score inconsistently. Getting it right makes your handover more accurate and your reassessments more meaningful.
The three components
The GCS assesses three responses, each scored separately. The total ranges from 3, no response at all, to 15, fully alert and oriented.
Eye opening, scored 1 to 4:
4: Opens eyes spontaneously.
3: Opens eyes to sound or voice.
2: Opens eyes to pressure.
1: No eye opening.
Verbal response, scored 1 to 5:
5: Oriented. Correctly gives their name, where they are and the month or year.
4: Confused. Talks in sentences but is disoriented.
3: Words. Says recognisable words that don't form sentences.
2: Sounds. Makes moans or groans only.
1: No verbal response.
Motor response, scored 1 to 6:
6: Obeys commands, such as squeezing your hand and letting go.
5: Localises. Moves a hand towards the source of pressure, above the level of the collarbone.
4: Normal flexion. Bends the arm at the elbow quickly in response to pressure.
3: Abnormal flexion. Slow, stereotyped bending of the arm.
2: Extension. Straightens the arm at the elbow.
1: No motor response.
Use a standard stimulus
When a patient does not respond to voice, apply a standardised physical stimulus rather than shaking them or using random painful stimuli. The current approach recommends fingertip pressure to assess eye opening and the motor response to a peripheral stimulus, and pressure on the trapezius muscle or the notch above the eye to test whether the patient localises. Using the same stimulus every time makes your scores comparable between assessments and between clinicians.
Report the three parts, not just the total. E3 V4 M6 tells the next clinician far more than 13.
Common scoring mistakes
Reporting only the total. Two patients with a GCS of 10 can have very different injuries. Always give the components.
Scoring the worst response. Score the best response you observe in each component.
Mixing up localising and normal flexion. Localising means the hand moves purposefully towards the stimulus and crosses the midline or rises above the collarbone.
Guessing the verbal score in patients who cannot speak. If the patient has an endotracheal tube or another reason they physically cannot talk, record the verbal score as not testable rather than 1.
Rushing. Give the patient time to respond before moving to a stronger stimulus.
Why the trend matters
A single GCS is a snapshot. Repeated scores show direction. A falling score, particularly a drop in the motor component, can be an early sign of rising pressure inside the skull, worsening hypoxia, hypoglycaemia or shock, and it needs prompt reassessment and escalation. Always look for a reversible cause, starting with airway, breathing, circulation and blood glucose. A GCS of 8 or less is often used as a marker that the patient may not be able to protect their own airway, but the decision about airway management should be based on the whole clinical picture.
A worked example
You find a patient after a fall. They open their eyes when you speak to them, but not before. They say words such as "leave me" but not sentences. When you apply trapezius pressure, they reach up and push your hand away. Their score is E3 V3 M5, a total of 11. Ten minutes later they only open their eyes to pressure and their arm bends slowly and stiffly at the elbow: E2 V3 M3, a total of 8. That drop, especially in the motor score, is the finding that should change your management and your urgency.
Special cases
Some patients cannot be scored normally, and the honest answer is to record why rather than guess:
Eyes swollen shut from facial injury: record eye opening as not testable.
An endotracheal tube or a severe facial injury: record the verbal score as not testable.
A language barrier, hearing loss or a pre existing condition such as aphasia or dementia: note this, because a low verbal score may be the patient's baseline.
Sedation, intoxication or a recent seizure: score what you see, but interpret it with that context in mind.
Severity bands in head injury
In traumatic brain injury, the GCS is often used to group severity: 13 to 15 is mild, 9 to 12 is moderate and 3 to 8 is severe. These bands are a guide only. A patient with a GCS of 14 can still have a serious bleed, so mechanism, symptoms and the trend over time matter as much as the number.
Children
Young children cannot answer orientation questions, so a paediatric version modifies the verbal score. A child who coos, babbles or interacts normally for their age scores 5, an irritable but consolable cry scores 4, crying only to pressure scores 3, moaning to pressure scores 2 and no response scores 1. Ask the carer what is normal for the child.
The GCS Pupils score
A newer addition, the GCS Pupils score, subtracts a point for each pupil that does not react to light, giving a range of 1 to 15. It combines two of the most important findings in head injury into one number, and it is worth knowing if your service or hospital uses it.
Conclusion
Learn the three components until you can score them without looking, use a standard stimulus, record the best response in each part and always report the breakdown as well as the total. Then reassess regularly. The trend in a patient's GCS is often more valuable than any single number.
References
Teasdale G, Jennett B. Assessment of coma and impaired consciousness: a practical scale. Lancet. 1974;2(7872):81.
Teasdale G, Maas A, Lecky F, Manley G, Stocchetti N, Murray G. The Glasgow Coma Scale at 40 years: standing the test of time. Lancet Neurol. 2014;13(8):844.
Reith FC, Van den Brande R, Synnot A, Gruen R, Maas AI. The reliability of the Glasgow Coma Scale: a systematic review. Intensive Care Med. 2016;42(1):3.
Institute of Neurological Sciences NHS Greater Glasgow and Clyde. Glasgow Coma Scale: do it this way. glasgowcomascale.org.
Brennan PM, Murray GD, Teasdale GM. Simplifying the use of prognostic information in traumatic brain injury. Part 1: The GCS Pupils score. J Neurosurg. 2018;128(6):1612.
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Disclaimer: This article is general education for students. It is not medical advice, and it does not replace your service's clinical practice guidelines, your educators or your local protocols.
