Glasgow Coma Scale (GCS): Scoring, Components and a Worked Example

The Glasgow Coma Scale (GCS) rates three responses: eye opening (1 to 4), verbal response (1 to 5) and motor response (1 to 6). Added together, the total runs from 3 to 15 (Glasgow Coma Scale site). It is a shared language for describing level of consciousness and for tracking change over time.

The scale

The Glasgow Coma Scale website lists the response levels for each of the three components, in order from best to worst (glasgowcomascale.org). The score ranges below come from a published table of the scale (PMC).

The lowest possible total is 3 and the highest is 15 (NIH FITBIR).

The site also describes a structured approach to assessment that uses defined criteria to assign each rating, which it says improves reliability (Glasgow structured approach).

Using it in NurseTools

The GCS tool is in clinical review and is not available yet. NurseTools is an iPhone app for nurses that is coming soon to the App Store, and nothing is downloadable yet. Only the BMI and MAP tools will be interactive at launch.

In the app, the GCS tool will appear locked. A release-gates timeline will show the steps a tool goes through before it opens:

1. Source and rights audit.
2. Clinical editorial review.
3. Independent testing.
4. Regulatory and App Store review.

A “Notify me when available” switch will let you ask to be told when the tool is released. Nothing unlocks a tool that has not passed review. NurseTools has no account, never asks for patient data and works offline.

Worked example

This example uses made-up numbers. It is not a patient.

Suppose an assessment finds:

• Eyes open to sound. That is the second level in the eye list, so E = 3.
• Speech is confused. That is the second level in the verbal list, so V = 4.
• The person localizes. That is the second level in the motor list, so M = 5.

Add the components: 3 + 4 + 5 = 12.

The Glasgow Coma Scale site recommends recording the components themselves, written as E3V4M5, and says the total (here, 12) hides detail because different combinations can add up to the same number (Recording GCS). For instance, E4V2M6 also totals 12 but describes a very different picture.

Now a second made-up case with an intubated person. Eyes open spontaneously (E4), the motor response obeys commands (M6), and the verbal response cannot be tested. It is recorded as E4 VNT M6. No total is reported.

Limits and common pitfalls

• Do not score an untestable component as 1 or 0. The Glasgow site says a component that cannot be tested, for example verbal response with an endotracheal tube or tracheostomy, is recorded as NT, and NT is not translated into 1 or zero in a sum (Glasgow structured approach).
• A total is not reported when any component is NT. The result would look falsely low and could confuse colleagues (NIH FITBIR). The trend in the components that can be assessed stays useful.
• NT can come from many causes. One article gives examples of eye swelling (eye), intubation (verbal) and paralysis (motor) (PMC).
• The total alone hides detail. Different component patterns share the same sum, so the components carry more information.
• Application varies between people. A study of staff caring for pediatric patients found considerable variation in how the scale was applied, with the verbal component the least consistent. Errors in single components produced totals off by up to 6 points, and most participants did not know a total cannot be calculated when a component is NT (PMC).
• Use the facility’s training and protocols. Consistent scoring depends on defined criteria and practice, not on a number alone.

Because GCS is still in clinical review in NurseTools, this page is for learning how the scale works. It is not a way to score a patient in the app.