Glasgow Coma Scale Calculator

GCS scoring (15-point scale)

Eye opening (1-4): 4 spontaneous, 3 to voice, 2 to pain, 1 none. Verbal (1-5): 5 oriented (knows person/place/time), 4 confused, 3 inappropriate words, 2 incomprehensible sounds, 1 none. Motor (1-6): 6 obeys commands, 5 localizes pain, 4 withdraws, 3 abnormal flexion (decorticate), 2 abnormal extension (decerebrate), 1 none. Total range: 3-15. Always document as E_V_M_ (e.g., E4V5M6).

Severity bands and trauma triage

Mild head injury: GCS 13-15. Most don't require ICU. Often discharge home with head-injury instructions. Moderate: GCS 9-12. Admission for observation, often imaging and neurosurgery consult. Severe: GCS ≤8 — by convention 'GCS 8, intubate' because the patient cannot protect the airway. ICU admission, immediate imaging, neurosurgery.

How to score 'best response' correctly

Use the BEST response across all extremities. If left arm localizes (5) and right arm withdraws (4), score 5. If the patient is intubated, document V as 'T' (intubated, cannot assess) — total can be reported as 'E_V_TM_' rather than a single number. Pediatric patients have a modified GCS for verbal responses (smiles/follows objects in infants).

Trending GCS over time

A SINGLE GCS is less informative than a trend. Document GCS at admission, at handoff, q2h-q4h depending on severity, and after any intervention. A drop of ≥2 points is clinically significant and warrants immediate provider notification — early sign of expanding intracranial hematoma.

How to perform an accurate GCS at the bedside

Three things separate a useful GCS from a number that misleads the team. First, score eye opening before you touch the patient — calling their name from the foot of the bed gives a different result than rubbing the sternum. The grading is hierarchical: spontaneous open (4) before voice (3) before pain (2). Second, use a standardized noxious stimulus. Trapezius squeeze and supraorbital pressure are the modern recommendations; sternal rub is widely used but produces bruising on chronically ill or elderly patients and yields the same clinical information. Third, score the best motor response across all four extremities. Hemiplegia from a prior stroke or unilateral fracture will artificially lower the motor score if you only check the affected side.

Documentation pitfalls: never report GCS as a single integer when one component is untestable. A patient who is intubated cannot give a verbal response — the correct documentation is "E4VTM6" with V scored as T (intubated). A patient with bilateral periorbital edema cannot be scored for eye opening — document "E(swollen)V5M6." Reporting a single number like "GCS 11" without component breakdown loses the clinical picture and obscures whether the deficit is verbal (often early aphasia or sedation) versus motor (often more ominous).

GCS in trauma triage and the 8-or-less rule

The Advanced Trauma Life Support (ATLS) curriculum classifies head injury by GCS: mild 13–15, moderate 9–12, severe ≤8. The phrase "GCS 8, intubate" reflects that patients with GCS ≤8 typically cannot protect their airway against aspiration. The rule is a guideline, not a mandate — a patient with isolated severe verbal deficit (E4V1M6 = GCS 11) may need intubation for airway concerns despite a higher number, while a transient post-ictal patient at GCS 7 may regain protective reflexes within minutes and not require intubation. Always pair GCS with airway assessment, gag reflex, ability to clear secretions, and clinical trajectory. The number guides; the clinical exam decides.

When GCS is unreliable: alternatives and adjuncts

GCS underperforms in several common scenarios. Sedation and chemical paralytics make verbal and motor scores meaningless — for ICU patients on continuous sedation, the FOUR (Full Outline of UnResponsiveness) score is more useful because it captures brainstem reflexes (pupillary, corneal) and respiratory pattern that GCS ignores. Pediatric GCS uses age-modified verbal categories: smiles or coos (5), irritable cry (4), inappropriate cry (3), grunts (2), none (1). For toxicology and post-arrest patients, the AVPU scale (Alert, Voice, Pain, Unresponsive) is faster but less granular. In suspected stroke, the NIH Stroke Scale (NIHSS) replaces GCS as the primary severity measure. Knowing which scale to use in which population is part of skilled neurologic assessment, and the GCS is the universal starting point even when a more specific tool follows.