PERC Rule for Pulmonary Embolism

Use the PERC rule to rule out PE if no criteria are present and pre-test probability is <15%.


The PERC rule is used to rule out pulmonary embolism in those patients where the clinical gestalt is that they are low risk (ie <15% risk of pulmonary embolism).

Pulmonary embolism can be ruled out if none of the following features are identified:

  • Age ≥50 years
  • Heart rate ≥100 bpm
  • Oxygen saturation <95%
  • Hemoptysis
  • Estrogen use
  • Prior DVT or PE
  • Unilateral leg swelling
  • Surgery/trauma within the previous four weeks

In patients with a low pre-test probability of PE who meet any of these criteria, further testing could be considered to more definitely rule out pulmonary embolism.


Kline JA et al.

Journal of Thrombosis and Haemostasis: JTH 2008, 6 (5): 772-80

The PERC Rule for Pulmonary Embolism calculator is created by QxMD.

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