How can I effectively use the Glasgow Coma Scale (GCS) to assess the severity of reduced consciousness in my patients?

Guideline-aligned answer with reasoning, red flags and references. Clinically reviewed by Dr Kola Tytler MBBS CertHE MBA MRCGP.

Posted: 22 August 2025Updated: 22 August 2025 Guideline-Aligned (High Confidence) Clinically Reviewed
Dr Kola Tytler MBBS CertHE MBA MRCGPClinical Lead • iatroX

To effectively utilize the Glasgow Coma Scale (GCS) for assessing the severity of reduced consciousness in your patients, follow these key steps:

  • Assess the three components separately: eye opening, verbal response, and motor response. Record each component score individually (e.g., E4, V4, M5) rather than only the total score to provide detailed clinical information .
  • Calculate and communicate the total GCS score out of 15: Always accompany the total score with the individual component scores in all documentation and communication to ensure clarity and accuracy .
  • Use the paediatric version of the GCS when assessing children: This includes a 'grimace' alternative to the verbal response to accommodate preverbal children .
  • Consider the patient’s baseline neurological status: For patients with pre-existing neurological conditions or cognitive impairments, establish their pre-injury baseline GCS if possible, as it may be less than 15 .
  • Recognize critical thresholds: A GCS score of 8 or less indicates severe impairment and necessitates early involvement of trained clinicians for advanced airway management and resuscitation . A score of 12 or less may warrant consideration of tranexamic acid administration .
  • Ensure timely assessment: Patients presenting with impaired consciousness (GCS <15) should be assessed immediately by trained staff, ideally within 15 minutes of arrival in emergency settings .
  • Use GCS scores to guide pre-alerts and transport decisions: For example, a GCS of 8 or less requires pre-alerting the receiving emergency department to prepare for appropriate care and imaging .

By systematically applying these principles, you can accurately assess and communicate the severity of reduced consciousness, facilitating appropriate and timely management of patients with head injury or other causes of impaired consciousness.

Educational content only. Always verify information and use clinical judgement.