Safety and Diagnostic Utility Pulmonary Embolism Rule-Out Criteria (PERC) and D-Dimer in Emergency Department

This study aimed to assess the diagnostic value and safety of using Pulmonary Embolism Rule-Out Criteria (PERC) in an emergency care setting.

We conducted a retrospective application of the PERC to the patients suspected of having pulmonary embolism (PE) and who underwent computed tomography pulmonary angiogram (CTPA) Karolinska University Hospital's emergency department (ED) from 2016 to 2017. The patient data, including D-dimer (DD) and ED waiting times were extracted from the Karolinska Venous Thromboembolism cohort (VTE cohort).

Among the 295 patients included in the cohort, 34 (11.5%) were diagnosed with PE. Of these 202 (68.5%) patients were PERC-positive, while 93 (31.5%) were PERC-negative. Among the 93 PERC-negative patients, three had PE; resulting in a sensitivity of 91% (95% CI: 0.77-0.97), a specificity of 34% (95% CI: 0.29-0.40), and a false negative rate (FNR) of 8.8%. Combining positive DD and PERC resulted in a sensitivity of 100% (95% CI: 0.86-1.00), a specificity of 23% (95% CI: 0.15-0.34), and no FNR. When patients classified as high risk for PE (determined by clinical gestalt) were excluded, no PEs were missed. The median total ED stay was 450 minutes in patients who underwent CTPA compared to 203 minutes in the reference group ( p < 0.0001).

Using the PERC rule along with DD testing in low-risk patients effectively rules out PE in ED without the need for further testing. Properly using PERC may significantly reduce patients' waiting time in the ED.