Aaron Graves, PhDude (Replica)

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pecarn calculator

Posted on February 16, 2026 by Admin

PECARN Pediatric Head Injury Calculator

Use this tool to estimate risk of clinically important traumatic brain injury (ciTBI) after minor blunt head trauma in children.

Enter age to show the appropriate PECARN criteria set.

Shared high-risk predictor

Age < 2 years predictors

Age 2 years and older predictors

Severe mechanism examples: motor vehicle crash with ejection/rollover/death of another passenger, pedestrian/bicyclist struck by vehicle (no helmet), fall >3 ft (<2 years) or >5 ft (≥2 years), high-impact object to head.
Important: This calculator is for educational support and should not replace clinical judgment, local protocols, observation, or specialist consultation.
PECARN is validated for children with minor blunt head trauma and initial GCS 14-15. Not intended for penetrating trauma, known bleeding disorders, anticoagulation, or unstable patients.

What is the PECARN calculator?

The PECARN calculator applies the Pediatric Emergency Care Applied Research Network clinical decision rule for head trauma. It helps identify children at very low risk for clinically important traumatic brain injury (ciTBI), where CT imaging can often be avoided.

The goal is to support safer care by reducing unnecessary radiation exposure while still catching serious injuries that require urgent imaging and treatment.

How this head injury rule works

PECARN separates children into two groups:

  • Under 2 years old
  • 2 years and older

Each age band has specific predictors. Based on your entries, the calculator classifies the result as high risk, intermediate risk, or very low risk for ciTBI.

High-risk output

If high-risk criteria are present, immediate CT is commonly recommended in the original pathway, alongside urgent physician evaluation.

Intermediate-risk output

If intermediate predictors are present, the typical approach is observation versus CT using shared decision-making, exam evolution, symptom progression, and caregiver preference.

Very low-risk output

If no relevant PECARN predictors are present, the child is in a very low-risk category where CT is often not indicated.

Input guide for each field

Age

Age determines which PECARN rule is used. Enter years as a decimal when needed (for example, 18 months = 1.5 years).

GCS score

The Glasgow Coma Scale captures level of consciousness. In PECARN, a GCS of 14 or less is a high-risk sign.

Altered mental status

This includes confusion, somnolence, agitation, repeated questioning, or slow responses.

Mechanism and symptom fields

Use the age-specific checkboxes carefully. “Severe mechanism” has a precise definition and should not be applied loosely.

When to use extra caution

  • Worsening neurological symptoms during observation
  • Persistent parental concern despite low-risk scoring
  • Intoxication, communication barriers, or unreliable history
  • Comorbidities that may increase bleeding or complicate exam

Clinical limitations

No score can replace bedside reassessment. PECARN is strongest when used in context: detailed neuro exam, serial observations, and informed discussion with caregivers.

Also remember that institutional policies differ. Some emergency departments combine PECARN with local pathways, point-of-care checklists, and trauma team protocols.

Quick FAQ

Does this calculator diagnose concussion?

No. It estimates risk of clinically important traumatic brain injury and need for CT pathway decisions, not concussion diagnosis.

Is vomiting always high risk?

Not by itself in children 2 years and older. In PECARN, vomiting is typically an intermediate-risk predictor.

Can I use this for adults?

No. This rule is pediatric-specific.

Bottom line

The PECARN calculator is a practical evidence-based support tool for pediatric minor head trauma triage. Use it to structure decisions, communicate risk, and avoid unnecessary CTs when appropriate—while keeping clinical judgment front and center.

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