GCS Calculator (Glasgow Coma Scale)

Created by Łukasz Białek, MD
Reviewed by Bogna Szyk
Last updated: Feb 15, 2022

Glasgow Coma Scale is one of the most important and fundamental scales in medicine used by almost every doctor to estimate patient's consciousness. Thanks to our GCS calculator, you also can do it in just three simple steps!

Check out also our other calculators with essential medical scales, such as the Apgar score or the MELD score!

What is the Glasgow Coma Scale? ##

In 1974, Graham Teasdale and Bryan J. Jennett, professors of neurosurgery at the University of Glasgow, published an article in Lancet - one of the most influential medical journals - in which they described and proposed a new scale to assess coma and state of consciousness. Since that time, due to its simplicity and feasibility, it has become an incredibly popular tool. Moreover, the GCS score is used as a part of other medical scales and scoring systems, such as Revised Trauma Score or APACHE II.

When to use GCS ##

Initially, Teasdale and Jennett destined Glasgow Coma Scale as an approach in the serial assessment of patients with traumatic brain injury. Nowadays doctors of nearly all specialties use it in their medical wards. GCS should be calculated:

  • after any major trauma
  • in lost consciousness
  • in suspicion of decortication or decerebration
  • in patients in a coma
  • in all patients in Intensive Care Units.

How to use the Glasgow Coma Scale calculator? ##

The GCS consists of 3 tests:

  • eye response (E4)
  • verbal response (V5)
  • motor response (M6)

Out of each test, you can get from 1 up to 4, 5 or 6 points respectively. The sum of values of the test is a GCS score.

Value Eye response Verbal response Motor response
1Does not open eyesMakes no sounds Makes no movements
2Opens eyes in response to pain Makes sounds Extension to painful stimuli
3Opens eyes in response to voice Words Abnormal flexion to painful stimuli
4Opens eyes spontaneously Confused, disoriented Flexion / Withdrawal to painful stimuli
5N/A Oriented, converses normally Localizes to painful stimuli
6N/A N/A Obeys commands

Let's look at the example!

Adult male after brain injury opens eyes when you speak to them, and can hold a conversation, though seems disoriented. Patient flexes elbow and wrist when you put pressure on the nail bed.

Such a patient receives 3 points for eye response, 4 points for verbal response and 3 points for motor response. GCS score = 10 pts

Interpretation of GCS score ##

The lowest possible GCS score is 3 and the highest is 15 points.
Glasgow Coma Scale enables to divide brain injuries into categories:

  • minor (GCS 13-15)
  • moderate (GCS 9-12)
  • severe (GCS 3-8)

GCS of 8 or less indicates to intubate a patient.

Controversy ##

GCS was not originally intended to be converted into a single score. Moreover, some researchers take issue with the scale's poor inter-rater reliability and lack of prognostic utility. It is worth noticing that the same GCS score will predict different mortality depending on the components, e.g. GCS of 4 with the components 1+1+2 (Eye+Verbal+Motor) predicts a mortality rate of 48% while GCS of 4 with the components 2+1+1 (Eye+Verbal+Motor) predicts a mortality rate of 19%.

Nevertheless, GCS is a routine and widespread test, which remains a standard of care in many clinical situations.

Łukasz Białek, MD
Eye response
Verbal response
Motor response
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