Glasgow Coma Scale (GCS) CalculatorAssess Brain Injury
Rapidly assess and quantify a patient’s level of consciousness and neurological functioning following acute brain injury or altered mental status.
Clinical Assessment
Select the patient’s neurological responses to generate the GCS Score and trauma classification.
Understanding the Glasgow Coma Scale
First published in 1974 by Graham Teasdale and Bryan Jennett at the University of Glasgow, the Glasgow Coma Scale (GCS) is the most widely adopted clinical scoring system used to objectively describe the extent of impaired consciousness in all types of acute medical and trauma patients. The scale assesses patients according to three aspects of responsiveness: eye-opening, motor, and verbal responses.
Clinical Interpretation & Brain Injury Severity
The GCS is routinely used to guide early management, track clinical trajectory, and provide prognostic information regarding Traumatic Brain Injury (TBI). The severity is classified as follows:
- Severe Head Injury (GCS 3–8): Indicates a coma. The classic clinical pearl is “GCS less than 8, intubate,” as these patients frequently lack the ability to protect their airway.
- Moderate Head Injury (GCS 9–12): Significant alteration in consciousness. Requires close monitoring, often in an ICU setting, and an immediate CT scan of the head.
- Mild Head Injury (GCS 13–15): Often correlates with concussions. While patients may appear stable, clinical vigilance is required for signs of acute deterioration (e.g., epidural hematoma).
Scoring Modifiers and the “NT” (Not Testable) Designation
| Condition | Impact on GCS Scoring |
|---|---|
| Intubation / Tracheostomy | The Verbal response cannot be tested. It is recorded as V1t (or NT). The maximum possible GCS becomes 11T. |
| Severe Facial Trauma / Edema | If the eyes cannot physically open due to swelling, the Eye response is recorded as NT (Not Testable) rather than a 1. |
| Language Barrier / Aphasia | Assessments must account for hearing loss, psychiatric conditions, or severe language barriers to prevent artificially low Verbal scores. |
Limitations of the GCS
While ubiquitous, the GCS has notable limitations. It is heavily influenced by systemic factors such as alcohol intoxication, illicit drug use, profound hypoxia, and shock. Furthermore, it does not assess pupillary reactivity or brainstem reflexes, which are crucial for a comprehensive neurological exam. Because of this, it is often supplemented with the FOUR Score (Full Outline of UnResponsiveness) in intensive care settings.
