PERC Rule Calculator
Pulmonary Embolism Rule-out Criteria for low-risk patients.
PERC Criteria
If ALL criteria are absent in a low-risk patient, PE can be excluded:
Important Prerequisite
PERC should ONLY be applied to patients already determined to be low-risk by:
- Wells score ≤4 (PE unlikely), OR
- Clinical gestalt <15% probability
PERC Status
PERC Negative
0 of 8 criteria present
PE Excluded?
Yes
D-dimer Needed?
No
Clinical Recommendation
All PERC criteria are negative. In low-risk patients (Wells ≤4 or gestalt <15%), PE can be ruled out without further testing. No D-dimer needed.
PERC Validation
- - Sensitivity: 97.4%
- - Specificity: 21.9%
- - NPV: 99.1%
- - Miss rate: <2% (acceptable threshold)
When NOT to Use PERC
- - Moderate or high-risk patients
- - Clinical gestalt ≥15%
- - Wells score >4
- - Patient with active anticoagulation