What is the Wells score for PE?

The Wells score for pulmonary embolism is a validated clinical prediction rule that combines seven weighted criteria into a single number estimating the pre-test probability of PE. It guides whether to order a D-dimer test or proceed directly to CT pulmonary angiography.

How is the Wells PE score interpreted?

In the three-tier model, 0 to 1 is low, 2 to 6 is moderate, and 7 or more is high probability. In the widely used two-tier model, a score of 4 or less is PE unlikely and over 4 is PE likely, which then drives the D-dimer versus CTPA decision.

What is a PE-unlikely result and what follows?

A two-tier score of 4 or less is PE unlikely. In these patients a negative high-sensitivity D-dimer can safely exclude PE without imaging. A positive D-dimer, or a PE-likely score, should be followed by CT pulmonary angiography or a ventilation-perfusion scan.

Why are some criteria worth three points?

Clinical signs and symptoms of DVT and the judgement that PE is the most likely diagnosis are the strongest predictors in the rule, so each carries three points. The other criteria such as tachycardia, immobilisation, and haemoptysis carry one to one and a half points.

Can I use the Wells PE score with PERC?

Yes. In very low-risk patients, the PERC (Pulmonary Embolism Rule-out Criteria) rule can be applied to avoid any testing. Otherwise the Wells score directs the D-dimer and CTPA pathway. Both tools support, rather than replace, clinical judgement.

Wells Score for Pulmonary Embolism

What the Wells PE score does

The Wells score for pulmonary embolism translates bedside clinical features into an estimated pre-test probability of PE. By stratifying patients before any test, it lets clinicians use D-dimer and CT pulmonary angiography (CTPA) appropriately — sparing low-risk patients unnecessary radiation and contrast, while ensuring high-risk patients move quickly to definitive imaging.

How it works

Each criterion adds the weighted points shown:

Clinical signs and symptoms of DVT (leg swelling and pain on palpation) — +3
PE is the most likely diagnosis (alternative diagnosis less likely than PE) — +3
Heart rate >100 beats per minute — +1.5
Immobilisation ≥3 days or surgery in the previous 4 weeks — +1.5
Previous objectively diagnosed DVT or PE — +1.5
Haemoptysis — +1
Malignancy (treatment within 6 months or palliative) — +1

The points are summed. In the three-tier model 0–1 is low, 2–6 is moderate, and ≥7 is high probability. In the two-tier model ≤4 is “PE unlikely” and >4 is “PE likely”.

Tips and example

A patient with PE as the most likely diagnosis (+3), heart rate 110 (+1.5), and recent surgery (+1.5) scores 6 — moderate probability (three-tier) and PE likely (two-tier), warranting CTPA. For a PE-unlikely score, a negative high-sensitivity D-dimer safely excludes PE without imaging. Always combine the score with the clinical picture, the PERC rule where appropriate, and your local PE pathway.