Wells Score for Pulmonary Embolism

About this calculator

Wells criteria for pulmonary embolism (PE) is a clinical assessment of PE pretest probability. Developed by Wells et al. (Thromb Haemost, 2000). Seven criteria with weights: clinical DVT signs (3), PE more likely than alternative (3), tachycardia >100 (1.5), immobilization or surgery in past 4 weeks (1.5), prior PE/DVT (1.5), hemoptysis (1), active cancer (1). Maximum 12.5. Three-tier interpretation. <2 – low probability (3-6%), 2-6 – intermediate (20-25%), >6 – high (60-65%). Two-tier: <=4 – unlikely, >4 – likely. Clinical algorithm. ESC 2019 recommends the two-tier model. PE unlikely + negative D-dimer (age-adjusted: 500 ng/mL up to age 50, age × 10 ng/mL after 50) – PE ruled out, no further workup. PE unlikely + positive D-dimer – CT pulmonary angiography. PE likely – proceed directly to CTPA without D-dimer. Alternative scores. Modified Geneva score – avoids the subjective "PE more likely than alternative" criterion. YEARS algorithm – simplified version with three clinical criteria plus D-dimer. PERC – PE rule-out rule for low-risk young patients without need for D-dimer. Each score has proponents; Wells remains most widespread internationally. Limitations. Subjective "PE more likely" criterion – depends on clinician experience. Not validated in pregnancy – use adapted YEARS-pregnancy algorithm with revised D-dimer thresholds. In active cancer effective D-dimer threshold is lower. Does not distinguish massive vs submassive PE – use sPESI and echo after PE confirmation for hemodynamic stratification.

Source

Wells PS et al. Derivation of a simple clinical model to categorize patients probability of pulmonary embolism. Thromb Haemost. 2000;83(3):416-420.

Formula version: wells-2000-v1

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