maratoolWells Score Calculator for Pulmonary Embolism
Wells criteria for clinical probability of pulmonary embolism.
References
- Wells PS, Anderson DR, Rodger M, et al. Derivation of a simple clinical model to categorize patients probability of pulmonary embolism. Thromb Haemost. 2000;83(3):416-420.
What is Wells Score Calculator for Pulmonary Embolism?
The Wells score for pulmonary embolism (PE) is a clinical decision rule that estimates the pre-test probability of acute PE. Originally derived by Wells et al. in 1998 and simplified in 2000, it scores seven criteria: clinical signs of DVT (3), PE most likely diagnosis (3), heart rate >100 (1.5), immobilization or recent surgery (1.5), prior DVT/PE (1.5), hemoptysis (1), and active malignancy (1). The three-tier interpretation classifies probability as low (<2), moderate (2–6), or high (>6); a dichotomized version uses ≤4 (PE unlikely) versus >4 (PE likely). PE-unlikely patients with a negative D-dimer can avoid CT pulmonary angiography.
How to use
- Check each criterion.
- The Wells score and probability category update instantly.
- Combine with D-dimer (low/moderate probability) or proceed to CTA (high probability).
Frequently asked questions
When should I use Wells for PE?
When a patient presents with possible pulmonary embolism (dyspnea, pleuritic chest pain, hemoptysis, leg swelling). It risk-stratifies before deciding on D-dimer vs imaging.
3-tier vs 2-tier Wells?
The 3-tier version uses < 2 / 2–6 / > 6 cutoffs. The 2-tier uses ≤ 4 (unlikely) vs > 4 (likely). The 2-tier is often used with high-sensitivity D-dimer.
What if Wells is low and D-dimer is negative?
Low Wells (or PE unlikely) + negative D-dimer effectively rules out PE without imaging in most patients.
When to apply PERC?
When the clinician’s pre-test probability is low (Wells < 2 OR clinical gestalt < 15%) and the patient meets all 8 PERC criteria, imaging and D-dimer can be safely avoided.
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