Evaluation of the pulmonary embolism rule-out criteria in a retrospective cohort at an urban academic hospital.
BACKGROUND
The pulmonary embolism rule-out criteria (PERC) is an 8-variable clinical decision rule that identifies patients at low risk for pulmonary embolism (PE) to prevent unnecessary diagnostic testing in the evaluation of suspected PE in the emergency department (ED). The objective of this study was to determine PERC's safety and diagnostic use in our institution's ED population.


METHODS
We performed a retrospective analysis on consecutive adult patients evaluated with computed tomographic angiography (CTA) for suspicion of PE at our ED during the dates January 1, 2011, to December 31, 2011. Patients negative for all 8 PERC criteria (ie, "PERC [-]") were considered to be at low risk for PE. All data were analyzed using SPSS-20 (SPSS Inc, Chicago, IL) to calculate the variables of interest and their respective 95% confidence intervals (95% CIs).


RESULTS
During the 12-month study period, 729 subjects were evaluated with CTA for suspicion of PE. Ten subjects were excluded because of nondiagnostic imaging studies. After exclusion, 719 subjects were available for analysis. Prevalence of PE was 4.5%. PERC (-) had a sensitivity of 96.9% (95% CI, 84.3%-99.4%), a negative predictive value of 98.8% (95% CI, 93.5%-99.8%), and a negative likelihood ratio of 0.26 (95% CI, 0.04-1.82) when used as an independent diagnostic test to exclude PE.


CONCLUSIONS
Use of PERC could have safely avoided 11.5% of CTAs, reducing potential patient harm, health care costs, and unnecessary diagnostic testing. Consistent with prior studies, PERC can be safely used to identify low-risk patients for whom further testing can be deferred.
School of Medicine, University of Missouri-Kansas City, Kansas City, MO, USA. Electronic address: bozartha@umkc.edu.
Andrew L
AL
Bozarth
School of Medicine, University of Missouri-Kansas City, Kansas City, MO, USA.
Navin
N
Bajaj
School of Medicine, University of Missouri-Kansas City, Kansas City, MO, USA.
Margaret R
MR
Wessling
School of Medicine, University of Missouri-Kansas City, Kansas City, MO, USA.
Dustin
D
Keffer
School of Medicine, University of Missouri-Kansas City, Kansas City, MO, USA.
Shais
S
Jallu
School of Medicine, University of Missouri-Kansas City, Kansas City, MO, USA.
Gary A
GA
Salzman
D000046:Academic Medical Centers / Q000706:statistics & numerical data; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003661:Decision Support Techniques; D003937:Diagnosis, Differential; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data*; D005260:Female; D006786:Hospitals, Urban / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011655:Pulmonary Embolism / Q000175:diagnosis*; D012189:Retrospective Studies; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed