Wells' criteria for pulmonary embolism

The Wells' criteria for pulmonary embolism is a risk stratification score to estimate the probability for pulmonary embolism (PE) in patients in which history and examination suggests PE is a diagnostic possibility. It provides a pre-test probability which, if deemed unlikely, can then be used in conjunction with a negative D-dimer to rule out PE avoiding imaging 1.


  • clinical signs and symptoms of DVT = 3
  • PE is most likely diagnosis or equally likely = 3
  • heart rate more than 100 = 1.5
  • iImmobilisation for 3 or more consecutive days or surgery in the previous 4 weeks = 1.5
  • previous objectively diagnosed PE or DVT = 1.5
  • haemoptysis = 1
  • malignancy (had treatment in the last 6 months or palliative) = 1

Score interpretation

Can be applied in either three tier or two tier models:

Three tier:

  • 0-1: low risk
  • 2-6: moderate risk
  • >6: high risk

Two tier:

  • ≤4: unlikely
  • ≥5: likely

In the three tier model:

  • low risk patients: pulmonary embolism rule-out criteria (PERC) can be considered as well as D-dimer
  • moderate risk: consider D-dimer or CT pulmonary angiography
  • high risk: D-dimer not recommended

In the two tier model:

  • unlikely: consider D-dimer
  • likely: consider CTPA
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Article information

rID: 53684
Systems: Chest, Cardiac
Synonyms or Alternate Spellings:
  • Wells score

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