What is the Wells score for PE?
The Wells score estimates the clinical probability of pulmonary embolism (PE). It guides who needs a D-dimer and who needs imaging.
NICE NG158 uses the two-level version. It sorts patients into “PE likely” or “PE unlikely”.
Wells PE criteria and points
| Criterion | Points |
|---|
| Clinical signs and symptoms of DVT | 3 |
| Alternative diagnosis less likely than PE | 3 |
| Heart rate over 100 | 1.5 |
| Immobilisation ≥3 days or surgery in last 4 weeks | 1.5 |
| Previous DVT or PE | 1.5 |
| Haemoptysis | 1 |
| Malignancy | 1 |
Interpreting the score (NICE NG158)
| Score | Result | Next step |
|---|
| Over 4 | PE likely | CTPA. Interim anticoagulation if there is any delay. |
| 4 or less | PE unlikely | D-dimer within 4 hours. CTPA if positive. |
The PERC rule
NICE suggests the PERC rule when clinical suspicion is low. If all eight criteria are negative, further testing may not be needed.
PERC applies only before any testing. It should not override a likely Wells score.
In primary care
- Most suspected PE needs same-day hospital assessment.
- Follow your local ambulatory VTE pathway.
- Check renal function and bleeding risk before anticoagulation.
- Use creatinine clearance to dose a DOAC.
Frequently asked questions
What Wells score means PE is likely?
A two-level Wells score over 4 means PE is likely. NICE advises a CTPA, with interim anticoagulation if it is delayed.
What do I do if the Wells PE score is 4 or less?
PE is unlikely. Request a D-dimer with results within 4 hours. Arrange a CTPA if the D-dimer is positive.
What is the difference between Wells PE and Wells DVT?
They are separate scores. Wells PE uses seven criteria and a threshold above 4. Wells DVT uses ten criteria and a threshold of 2.
Can I use the Wells score in pregnancy?
It is not validated in pregnancy. Follow RCOG guidance and local pathways for suspected PE in pregnancy.
What is the PERC rule?
Eight criteria that, when all negative in low-suspicion patients, suggest no further PE testing is needed.
References
- NICE. Venous thromboembolic diseases: diagnosis, management and thrombophilia testing. NICE guideline NG158, 2020 (updated 2023). nice.org.uk/guidance/ng158
- Wells PS, Anderson DR, Rodger M, et al. Derivation of a simple clinical model to categorize patients probability of pulmonary embolism. Thromb Haemost 2000;83(3):416–20.
- Kline JA, Mitchell AM, Kabrhel C, et al. Clinical criteria to prevent unnecessary diagnostic testing in emergency department patients with suspected pulmonary embolism. J Thromb Haemost 2004;2(8):1247–55.
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