Article Text

Download PDFPDF
A retrospective analysis of the combined use of PERC rule and Wells score to exclude pulmonary embolism in the Emergency Department


Background The pulmonary embolism rule-out criteria (PERC) rule is an eight-factor decision rule to support the decision not to order a diagnostic test when the gestalt-based clinical suspicion on pulmonary embolism (PE) is low.

Methods In a retrospective cohort study, we determined the accuracy of a negative PERC (0) in patients with a low Wells score (<2) to rule-out PE, and compared this to the accuracy of the default algorithm used in our hospital (a low Wells score in combination with a negative D-dimer).

Results During the study period, 377 patients with a Wells score <2 were included. CT pulmonary angiography (CTPA) was performed in 86 patients, and V/Q scintigraphy in one patient. PE was diagnosed in 18 patients. 78 patients (21%) had a negative PERC score. When further diagnostic studies would have been omitted in these patients, two (subsegmental) PEs would have been missed, resulting in a sensitivity of 89% (64%–98%) and a negative likelihood ratio (LR−) of 0.52 (0.14–1.97). The default algorithm missed one (subsegmental) PE, resulting in a sensitivity of 95% (71%–99%) and an LR− of 0.25 (0.04–1.73).

Conclusions The combination of a Wells score <2 and a PERC rule of 0 had a suboptimal sensitivity for excluding PE in our sample of patients presenting in the ED. Further studies are warranted to test this algorithm in larger populations.

  • pulmonary embolism
  • thrombo-embolic disease, diagnosis

Statistics from

Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.