Wells criteria are the most widely used way to estimate pre-test probability of PE. “PE unlikely” (4 or less) combined with a normal D-dimer safely rules out PE; “PE likely” patients go straight to CT pulmonary angiography.
How to use the Wells Score for Pulmonary Embolism
- Clinical signs and symptoms of DVT
- PE is the most likely diagnosis
- Heart rate above 100 bpm
- Immobilisation (3+ days) or surgery in the past 4 weeks
- Previous DVT or PE
- Haemoptysis
- Malignancy (treated within 6 months or palliative)
Results update as you type, and every field accepts the units shown in its menu.
How it works
Each answer carries the points shown in the published score. The calculator adds them up and maps the total to the published interpretation.
Scoring table
| Item | Answers and points |
|---|---|
| Clinical signs and symptoms of DVT | No = 0; Yes = 3 |
| PE is the most likely diagnosis | No = 0; Yes = 3 |
| Heart rate above 100 bpm | No = 0; Yes = 1.5 |
| Immobilisation (3+ days) or surgery in the past 4 weeks | No = 0; Yes = 1.5 |
| Previous DVT or PE | No = 0; Yes = 1.5 |
| Haemoptysis | No = 0; Yes = 1 |
| Malignancy (treated within 6 months or palliative) | No = 0; Yes = 1 |
Inputs explained
| Field | What to enter |
|---|---|
| Clinical signs and symptoms of DVT | Choose one: No, Yes |
| PE is the most likely diagnosis | Choose one: No, Yes |
| Heart rate above 100 bpm | Choose one: No, Yes |
| Immobilisation (3+ days) or surgery in the past 4 weeks | Choose one: No, Yes |
| Previous DVT or PE | Choose one: No, Yes |
| Haemoptysis | Choose one: No, Yes |
| Malignancy (treated within 6 months or palliative) | Choose one: No, Yes |
Health note: this calculator is for education and screening only and is not a diagnosis or treatment advice. Discuss your results with a qualified clinician.
Formula
Score = sum of the points for each item
Worked example
Inputs — Clinical signs and symptoms of DVT: No; PE is the most likely diagnosis: Yes; Heart rate above 100 bpm: No; Immobilisation (3+ days) or surgery in the past 4 weeks: No; Previous DVT or PE: No; Haemoptysis: No; Malignancy (treated within 6 months or palliative): No.
Results — Wells score = 3 / 12.5; Three-tier probability = Moderate (about 16%); Two-tier model = PE unlikely – check D-dimer.
Key terms
- CTPA
- CT pulmonary angiography.
Frequently asked questions
What is a high Wells score for PE?
Above 6 (three-tier) or above 4 (two-tier "PE likely").
What does "PE is the most likely diagnosis" mean?
That no alternative diagnosis is more likely than PE, in the clinician's judgement.
Can a D-dimer rule out PE?
Yes, when the Wells score is 4 or less and the D-dimer is normal.