Wells score for pulmonary embolism
Estimate the clinical probability of pulmonary embolism (PE) in a patient with suspected PE. Tick the criteria that apply to see the Wells score, its three-level category and whether PE is likely or unlikely.
How this Wells score for PE calculator works
This Wells score calculator uses the clinical prediction rule for pulmonary embolism published by Wells and colleagues in Thrombosis and Haemostasis in 2000. The team ran a logistic regression on 40 clinical variables in a random 80% of patients from a prospective cohort with suspected PE, kept the seven variables below, and checked the result in the remaining 20%. Each criterion that is present adds its points, so the score runs from 0 to 12.5.
Wells score = 3 (clinical symptoms of DVT) + 3 (no alternative diagnosis) + 1.5 (heart rate over 100) + 1.5 (immobilization or surgery in the previous 4 weeks) + 1.5 (previous DVT or PE) + 1 (hemoptysis) + 1 (malignancy)
Add only the points for criteria that are present. DVT = deep vein thrombosis.
Wells PE score categories
The Wells PE score has two published interpretations from the same paper. The three-level version sorts patients into low, moderate and high clinical probability. The two-level version splits them into PE unlikely (4 or less) and PE likely (over 4), and was built so that PE unlikely patients with a negative D-dimer would have PE in under 2% of cases. In the derivation set, 7.8% of patients scoring 4 or less had PE, and 2.2% (95% CI 1.0% to 4.0%) when the SimpliRED D-dimer was also negative; the rate was 1.7% in the validation set. That combination covered 46% of the study patients.
| Wells score | Three-level | Two-level |
|---|---|---|
| Under 2 | Low probability | PE unlikely |
| 2 to 4 | Moderate probability | PE unlikely |
| 4.5 to 6 | Moderate probability | PE likely |
| Over 6 | High probability | PE likely |
For the three-level version, a score under 2 with a negative D-dimer gave a PE rate of 1.5% (95% CI 0.4% to 3.7%) in the derivation set and 2.7% (95% CI 0.3% to 9.0%) in the validation set, but this applied to only 29% of patients.
Limits of the Wells score for PE
The Wells score for PE was derived in patients who were already suspected of having PE, so it is not a screening tool for people without that suspicion. Its largest item, no alternative diagnosis, is a clinician judgment worth 3 points, so two clinicians can score the same patient differently. The original cut-offs were paired with the SimpliRED D-dimer, and the score estimates probability before testing; it does not confirm or rule out PE on its own. The two-level rule was later tested in a management study in 12 Dutch centers (the Christopher study), where PE unlikely with a normal D-dimer occurred in 32.0% of 3306 patients and 0.5% of those left untreated had nonfatal venous thromboembolism within 3 months.
Questions
What is a high Wells score for PE?
On the three-level scale, a score over 6 is high clinical probability. On the two-level scale, any score over 4 counts as PE likely.
What does a Wells score of 4 or less mean?
PE unlikely. In the original paper, 7.8% of these patients had PE overall, and about 2% of those who also had a negative SimpliRED D-dimer.
Why are some points 1.5?
The original paper assigned the points from its regression analysis: 3 for clinical symptoms of DVT and for no alternative diagnosis, 1.5 for heart rate over 100, recent immobilization or surgery and previous DVT or PE, and 1 for hemoptysis and malignancy.
Is this the same as the Wells score for DVT?
No. Wells and colleagues published a separate rule for suspected deep vein thrombosis, with different criteria and cut-offs. This page scores the PE rule only.
Is my data sent anywhere?
No. The calculation runs in your browser, and the boxes you tick are not sent or stored.
Sources
- Wells PS, Anderson DR, Rodger M, et al. Derivation of a simple clinical model to categorize patients probability of pulmonary embolism: increasing the models utility with the SimpliRED D-dimer. Thromb Haemost. 2000;83(3):416–420. doi:10.1055/s-0037-1613830 · PubMed 10744147
- van Belle A, Büller HR, Huisman MV, et al. Effectiveness of managing suspected pulmonary embolism using an algorithm combining clinical probability, D-dimer testing, and computed tomography. JAMA. 2006;295(2):172–179. doi:10.1001/jama.295.2.172