Differentiating low-risk and no-risk PE patients: the PERC score.
BACKGROUND
Pulmonary embolism (PE) remains one of the most challenging diagnoses in emergency medicine. The Pulmonary Embolism Rule-out Criteria (PERC) score, a decision aid to reliably distinguish low-risk from very low-risk PE patients, has been derived and validated.


OBJECTIVE
Can a subset of patients with sufficiently low risk for PE be identified who require no diagnostic testing?


METHODS
The PERC score derivation and validation trials were located using PubMed and Web of Science. A critical appraisal of this research is presented.


RESULTS
One single-center and another multi-center validation trial both confirmed that the eight-item PERC score identified a very low-risk subset of patients in whom PE was clinically contemplated with a negative likelihood ratio 0.17 (95% confidence interval 0.11-0.25) in the larger trial. If applied, the rule would have identified 20% of potential PE patients as very low risk.


CONCLUSIONS
The PERC score provides clinicians with an easily remembered, validated clinical decision rule that allows physicians to forego diagnostic testing for pulmonary embolus in a very low-risk population.
Carpenter
Christopher R
CR
Washington University School of Medicine in St. Louis, St. Louis, Missouri, USA.
Keim
Samuel M
SM
Seupaul
Rawle A
RA
Pines
Jesse M
JM
D000328:Adult; D000933:Antifibrinolytic Agents; D003937:Diagnosis, Differential; D004636:Emergency Service, Hospital; D005189:False Positive Reactions; D005260:Female; D005338:Fibrin Fibrinogen Degradation Products; D006801:Humans; D010092:Oximetry; D011655:Pulmonary Embolism / Q000175:diagnosis*; D018570:Risk Assessment; D014057:Tomography, X-Ray Computed
D000933:Antifibrinolytic Agents; D005338:Fibrin Fibrinogen Degradation Products; C036309:fibrin fragment D