PECARN Head Injury Calculator
Identify children at very low risk of clinically important traumatic brain injury (ciTBI) to minimize unnecessary CT scans.
How to Use This Calculator
Determine age category
PECARN uses different criteria for children younger than 2 years vs 2 years and older.
Assess key clinical findings
Altered mental status or signs of skull fracture automatically place child in high-risk category.
Use observation judiciously
Observation can safely reduce CT use in intermediate-risk patients if close monitoring is available.
Frequently Asked Questions
What defines altered mental status?
GCS <15, agitation, somnolence, repetitive questioning, or slow response to verbal communication.
What counts as severe mechanism?
Pedestrian/bicyclist without helmet struck by vehicle, MVC with ejection, death of another passenger, rollover, fall >3 ft (<2y) / >5 ft (≥2y), head struck by high-impact object.
Is CT ever mandatory?
Consider CT if GCS <15, signs of skull fracture, or worsening symptoms. Clinical judgement prevails.
How reliable is PECARN?
Sensitivity 99.9% for clinically-important TBI in the validation cohort; CT use reduced by ~25%.
Can I apply PECARN to intoxicated or bleeding disorders?
Use caution; such patients were excluded from original study. Consider CT despite rule.