Wells score for pulmonary embolism
The Wells score estimates the pretest probability of pulmonary embolism (PE) and helps guide the next test, such as D-dimer or CT. The score is not a diagnosis.
Wells score
Enter the values to see the result.
This tool assists calculation. It does not replace clinical judgement and is not a treatment instruction. Check against your institution protocol, reference ranges, and prescribing information. Clinical decisions belong to the treating clinician.
Interpreting the result
- Low probability — Score under 2. Consider D-dimer per protocol.
- Moderate probability — Score 2 to 6.
- High probability — Score over 6. Imaging is usually needed.
Formula
Signs of DVT 3, PE most likely 3, heart rate over 100 is 1.5, immobilization/surgery in 4 weeks 1.5, previous DVT/PE 1.5, hemoptysis 1, active malignancy 1. Three tiers: under 2 low, 2 to 6 moderate, over 6 high.
Frequently asked questions
Does Wells use the 3-tier or 2-tier version?
Both exist. The 3-tier version splits low/moderate/high; the 2-tier version splits PE unlikely (4 or fewer) and PE likely (over 4). This tool shows the 3-tier version.
Does a low Wells score rule out PE?
Not on its own. Wells guides the next step (for example D-dimer) per protocol, and the decision belongs to the clinician.