Wells Score for PE Calculator - Pulmonary Embolism Risk Stratification

What Is the Wells Score for Pulmonary Embolism (PE)?

The Wells Criteria for Pulmonary Embolism is a validated clinical decision rule used by emergency physicians and clinicians to assess the pretest probability of acute pulmonary embolism in hemodynamically stable patients presenting with symptoms such as pleuritic chest pain, dyspnea, or hypoxia.

By stratifying patients into risk tiers, clinicians can determine whether a high-sensitivity D-dimer blood test can safely exclude PE (saving patients from unnecessary intravenous contrast and radiation) or if immediate imaging with CT Pulmonary Angiography ($\text{CTPA}$) or Ventilation-Perfusion ($\text{V/Q}$) scanning is warranted.

For deep vein thrombosis risk stratification, use our complementary Padua Prediction Score Calculator or explore our CHA2DS2-VASc Score Calculator.

Wells Criteria Scoring Breakdown

Clinical Criterion	Definition	Points
Clinical signs / symptoms of DVT	Leg swelling, unilateral calf pain, pain with deep palpation	+3.0
PE is #1 diagnosis or equally likely	Clinician judgment: alternative diagnosis is less likely than PE	+3.0
Heart rate > 100 bpm (Tachycardia)	Tachycardic baseline on exam or triage vital signs	+1.5
Immobilization or surgery	Bedridden $\ge 3$ consecutive days or surgery within past 4 weeks	+1.5
Previous objective DVT / PE	Documented ultrasound, CT, or V/Q-proven historical DVT or PE	+1.5
Hemoptysis	Coughing up blood or blood-tinged sputum	+1.0
Malignancy	Active cancer, palliative treatment, or treatment within past 6 months	+1.0

Risk Stratification & Diagnostic Pathways

Two-Tier Model: PE Unlikely ($\le 4.0$ Points)

PE prevalence is ~12%. Guideline pathway: Order a high-sensitivity D-dimer test (or age-adjusted D-dimer: $\text{Age} \times 10\text{ ng/mL}$ for patients over 50). If D-dimer is normal, PE is safely ruled out without imaging. If D-dimer is elevated, proceed to CTPA.

Two-Tier Model: PE Likely ($> 4.0$ Points)

PE prevalence is ~37% to 40%. Guideline pathway: Proceed directly to diagnostic imaging with CT Pulmonary Angiography ($\text{CTPA}$) or V/Q scanning. A negative D-dimer is not considered safe to rule out PE in high pretest probability patients.

Frequently Asked Questions

What is the difference between the 2-tier and 3-tier Wells score?

The 2-tier model simplifies stratification into 'PE Unlikely' (0-4 pts) and 'PE Likely' (>4 pts) and is the standard in most modern clinical guidelines. The 3-tier model splits risk into Low (<2), Moderate (2-6), and High (>6).

Can D-dimer rule out PE in high-risk patients?

No. In patients with a high pretest probability (Wells score > 4.0 or > 6.0), the false-negative rate of D-dimer is too high to safely rule out PE without diagnostic imaging like CTPA.

When should the PERC rule be used instead?

The Pulmonary Embolism Rule-out Criteria (PERC) rule is used only in patients already determined to have very low clinical probability (Wells score < 2 or PE Unlikely) to avoid even ordering a D-dimer test.

Is Wells score applicable to pregnant patients?

In pregnancy, modified diagnostic algorithms (such as the YEARS algorithm or pregnancy-adapted YEARS criteria) are preferred, as baseline D-dimer levels naturally rise throughout gestation.

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Wells PE Calculator