Wells PE

Pre-test probability assessment for pulmonary embolism

Indication

id: cancer; label: Active cancer (treatment within 6 months or palliative); type: yesno; points: 1
id: immobilized; label: Immobilization (≥3 days) or surgery in past 4 weeks; type: yesno; points: 1.5
id: prior; label: Prior DVT or PE; type: yesno; points: 1.5
id: hemoptysis; label: Hemoptysis; type: yesno; points: 1
id: hr100; label: Heart rate > 100; type: yesno; points: 1.5
id: dvtsigns; label: Clinical signs of DVT (leg swelling, pain with palpation); type: yesno; points: 3
id: alternative; label: PE is #1 diagnosis or equally likely; type: yesno; points: 3

function(score) { if (score <= 1) return { risk: score + ' points', tier: 'Low Probability', action: 'Consider PERC rule. If PERC negative, no further workup. If PERC positive, obtain D-dimer.', color: 'green' }; if (score <= 6) return { risk: score + ' points', tier: 'Moderate Probability', action: 'Obtain D-dimer. If positive (>500 or age-adjusted), proceed to CTA.', color: 'yellow' }; return { risk: score + ' points', tier: 'High Probability', action: 'Proceed directly to CTA. Do NOT rely on D-dimer to rule out.', color: 'red' }; }

Wells ≤1 + PERC negative = PE effectively ruled out without any testing
Wells ≤4 with negative D-dimer has >99% negative predictive value
Age-adjusted D-dimer cutoff: age × 10 (for patients >50 years)
The subjective criterion (#7) is the strongest predictor — be honest with your gestalt

Wells et al., Thromb Haemost 2000; ACEP Clinical Policy 2018. Last reviewed: 2024-10-01