RT Journal Article SR Electronic T1 A retrospective analysis of the combined use of PERC rule and Wells score to exclude pulmonary embolism in the Emergency Department JF Emergency Medicine Journal JO Emerg Med J FD BMJ Publishing Group Ltd and the British Association for Accident & Emergency Medicine SP 696 OP 701 DO 10.1136/emermed-2016-205687 VO 33 IS 10 A1 Theunissen, JMG A1 Scholing, C A1 van Hasselt, WE A1 van der Maten, J A1 ter Avest, E YR 2016 UL http://emj.bmj.com/content/33/10/696.abstract AB 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.