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Wells score for pulmonary embolism
Assigns a pre-test probability for pulmonary embolism and decides whether the next step is a D-dimer or straight to imaging.
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Opens the Wells Score for PE card in the ResusDoc Clinical Scores app — scores as you tap, with the interpretation and next steps.
What it is used for
The Wells score for PE is the entry point to the NICE NG158 two-level pathway for suspected pulmonary embolism in adults. Seven weighted criteria produce a total that places the patient in one of two groups — 'PE likely' or 'PE unlikely' — and it is that dichotomy, not the raw number, that determines management. The critical practical point is that a D-dimer is only a rule-out test in the 'unlikely' group; using it in the 'likely' group to avoid imaging is a recognised source of missed PE.
The seven criteria (weighted)
| Component | Points |
|---|---|
| Clinical signs of DVTLeg swelling, tenderness | 3 |
| Alternative diagnosis less likely than PEClinical judgement | 3 |
| Heart rate above 100 bpm | 1.5 |
| Immobilisation 3 days or more, or surgery in the last 4 weeks | 1.5 |
| Previous DVT or PE | 1.5 |
| Haemoptysis | 1 |
| MalignancyTreated within 6 months, or palliative | 1 |
Maximum 12.5 points. The threshold that matters is 4.
How the score is interpreted
More than 4
PE likely
Proceed directly to CTPA (or V/Q if CTPA is contraindicated). Do not use a D-dimer to rule out. Anticoagulate while awaiting imaging if there is no contraindication.
4 or less
PE unlikely
Perform a D-dimer. If negative, PE is excluded — look for an alternative diagnosis. If positive, proceed to CTPA (or V/Q).
When not to use it
- The two-level pathway is the NICE-recommended UK form; older three-level low/moderate/high cut-offs are not interchangeable with it.
- The 'alternative diagnosis less likely' item is subjective and carries 3 points — it is the single largest source of inter-rater variation.
- Not validated in pregnancy; follow a dedicated pathway instead.
Source: Wells Score · NICE NG158 two-level pathway · RCEM
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