Pulmonary embolism bedside decision support
PE Rule-Out Toolkit for Wells Score and PERC
Combine the Wells Score for pulmonary embolism and PERC criteria to support low-risk PE rule-out, D-dimer decisions, and imaging pathway guidance.
Use this page alongside the ABG Analyzer, A–a Gradient calculator, ROX Index calculator, and Causes of Hypoxemia when PE is part of the hypoxemia or dyspnea differential.
Step 01
Wells Score for PE
Select clinical findings and risk factors.
Current score
0.0
Step 02
PERC Rule
PERC is intended only for patients who are already low risk by clinician gestalt.
Current PERC
Negative
How to use Wells and PERC together
Wells Score estimates pretest probability for pulmonary embolism using clinical findings and risk factors. PERC is different: it is only meant for patients who are already low risk by clinician gestalt.
If Wells risk is moderate or high, PERC should not be used as the rule-out strategy. Those patients generally need a D-dimer or imaging pathway based on local protocol and patient-specific factors.
Clinical caution
Clinical decision rules support bedside assessment but do not replace judgment. Consider hemodynamic stability, pregnancy, anticoagulation status, renal function, contrast risk, imaging availability, and local protocols.
High-risk presentations should not be delayed by decision rules when urgent imaging or empiric treatment is clinically indicated.