Wells Score for Pulmonary Embolism
Calculates the pre-test probability of pulmonary embolism (PE) using the Wells criteria to guide diagnostic testing decisions.
Clinical Criteria
Minimum of leg swelling and pain with palpation of the deep veins
An alternative diagnosis is less likely than PE
Heart rate greater than 100 beats per minute
Immobilization for at least 3 consecutive days OR surgery within the past 4 weeks requiring general or regional anesthesia
Previously objectively documented DVT or PE
Coughing up blood
Cancer treatment ongoing, within 6 months, or palliative
Point Values
Wells PE Score
Enter values to calculate
About This Calculator
The Wells Score for Pulmonary Embolism is a validated clinical prediction rule that stratifies patients into PE probability categories. Developed by Dr. Phil Wells and colleagues, it helps clinicians determine the appropriate diagnostic workup for patients with suspected PE.
The score uses clinical and historical features to estimate the likelihood of PE: • Low probability patients may be safely evaluated with D-dimer alone • Moderate probability typically requires D-dimer with possible imaging • High probability patients should proceed directly to CT pulmonary angiography (CTPA)
Two scoring systems exist: • Traditional three-tier: Low (0-1), Moderate (2-6), High (≥7) • Simplified two-tier (PE Unlikely/Likely): ≤4 vs >4
The Wells PE score is most validated in outpatient and emergency department settings. It should be used with clinical judgment, as PE can occur even with low scores.
Key principle: If PE is clinically suspected despite a low Wells score, further testing is warranted.
Formula
Wells PE Score = Sum of present criteria (variable points)Points are assigned as follows: • Clinical signs/symptoms of DVT: +3 points • PE is #1 diagnosis or equally likely: +3 points • Heart rate >100 bpm: +1.5 points • Immobilization ≥3 days or surgery in past 4 weeks: +1.5 points • Previous DVT or PE: +1.5 points • Hemoptysis: +1 point • Malignancy (treatment within 6 months or palliative): +1 point Traditional interpretation: Low (0-1), Moderate (2-6), High (≥7) Simplified interpretation: PE Unlikely (≤4), PE Likely (>4)
Clinical Considerations
- •The Wells score is validated for non-pregnant adults
- •Clinical judgment should override scoring in high-suspicion cases
- •Age-adjusted D-dimer cutoffs may improve specificity in elderly patients
- •Patients with high suspicion require imaging regardless of score
- •Consider alternative diagnoses even with high Wells scores
- •PERC rule may be applied before Wells in very low-risk patients
Limitations
- •Subjective assessment of "alternative diagnosis less likely"
- •Not validated in pregnant patients
- •May underperform in hospitalized or post-operative patients
- •Does not account for all risk factors (e.g., estrogen use, thrombophilia)
- •Inter-observer variability in clinical assessment
- •Original validation used V/Q scans; CTPA is now standard
Interpretation Guide
| Range | Classification | Recommendation |
|---|---|---|
| <-2 | Low Probability | Low pre-test probability. Check highly-sensitive D-dimer. If negative, PE is effectively ruled out. If positive, proceed to CTPA. |
| 2-6 | Moderate Probability | Moderate pre-test probability. Check D-dimer if available. If positive or high clinical suspicion, proceed to CTPA. |
| 6-20 | High Probability | High pre-test probability. Proceed directly to CT pulmonary angiography (CTPA). Consider empiric anticoagulation while awaiting imaging. |
Frequently Asked Questions
What is the Wells Score for PE?
The Wells Score for PE is a clinical prediction rule that estimates the probability of pulmonary embolism based on clinical signs, symptoms, and risk factors. It helps guide decisions about D-dimer testing and imaging.
Can a negative D-dimer rule out PE?
In low-probability patients (Wells ≤4), a negative highly-sensitive D-dimer effectively rules out PE without need for imaging. In high-probability patients, imaging is needed regardless of D-dimer results.
What imaging is used to diagnose PE?
CT pulmonary angiography (CTPA) is the gold standard for diagnosing PE. It is highly sensitive and specific, and also provides information about clot burden and right ventricular strain. V/Q scanning is an alternative when CTPA is contraindicated.
Should I start anticoagulation before imaging?
In patients with high clinical suspicion for PE and hemodynamic stability, it is reasonable to start anticoagulation while awaiting imaging, particularly if there will be a delay in obtaining CTPA. Discuss with your clinical team.
What is the difference between Wells PE and Wells DVT?
The Wells PE score assesses probability of pulmonary embolism in the lungs, while Wells DVT assesses probability of deep vein thrombosis in the legs. They use different criteria and scoring. A patient can have DVT without PE, or PE without clinically evident DVT.
References
1. Wells PS, Anderson DR, Rodger M, et al.. Derivation of a simple clinical model to categorize patients probability of pulmonary embolism. Thrombosis and Haemostasis. 2000. doi: 10.1055/s-0037-1613917
View Source →2. Wells PS, Anderson DR, Rodger M, et al.. Excluding pulmonary embolism at the bedside without diagnostic imaging. Annals of Internal Medicine. 2001. doi: 10.7326/0003-4819-135-2-200107170-00010
View Source →3. Konstantinides SV, Meyer G, Becattini C, et al.. European Society of Cardiology Guidelines for the diagnosis and management of acute pulmonary embolism. European Heart Journal. 2020. doi: 10.1093/eurheartj/ehz405
View Source →Last updated: 2025-01-15
Auto-Calculate Wells PE in Your Clinical Notes
PatientNotes AI automatically captures patient data during your visit and calculates relevant clinical values directly in your documentation. No manual entry needed—just review and approve.
7-day free trial • No credit card required • HIPAA compliant