What is the Glasgow Coma Scale?

The Glasgow Coma Scale (GCS) is used to assess the level of consciousness after a person has suffered from a brain injury. It uses a system of scoring based on responses to certain stimuli and has proven highly useful to medical professionals since 1974. Nurse.org offers the following information on the GCS and how it’s used.

How it works

The person providing the GCS performs tests that assess the function of three criteria. These are motor response, verbal response, and eye-opening. At the end of testing a score is tallied which indicates a person’s level of impairment. A GCS ranging from 3 to 8 is considered to be a severe level of injury. Moderate injuries receive scores between 9 and 12, while mild injuries receive scores between 13 and 15.

When it’s used

Upon being admitted to a hospital after a serious brain injury GCS should be administered as soon as possible. It should also occur every four hours until medical staff is satisfied by the result. Multiple departments should be consulted in terms of the results, including neurology, emergency, and nursing personnel. Prior testing should be properly documented so it can be compared to upcoming tests.


For some patients, scoring can be altered by certain factors. For instance, inebriation caused by drugs and/or alcohol can disrupt a person’s normal stimulus response. Problems with speech and hearing can also be an issue, as can language barriers. Damage to the spinal cord that causes total or partial paralysis also impacts scoring. Despite these limitations, the GCS is still heavily relied upon by healthcare personnel.