Emergency medicine · Pulmonary embolism rule-out
PERC Rule
Check all eight Pulmonary Embolism Rule-out Criteria only after the clinician has established a low pretest probability for PE.
Patient factors
Select one answer per row
Private by design. Values are calculated on this device and are not saved or sent to analytics.
Result
Complete all factors
The score and its interpretation band will appear here.
Evidence packet
What this tool is based on
This versioned record keeps the citations, equation or decision rule, units, test coverage, intended population, and exclusions attached to the tool.
How evidence review works →Patients already assessed by an appropriate clinician as having a low pretest probability for pulmonary embolism within a validated diagnostic pathway.
Eight binary criteria: age ≥50, pulse ≥100/min, oxygen saturation <95%, unilateral leg swelling, hemoptysis, recent surgery/trauma, prior VTE, and exogenous hormone use.
Age in years, pulse in beats/min, and oxygen saturation in percent; remaining criteria are categorical.
All eight criteria, exact cutoffs, all-negative state, one-or-more-positive state, and complete-answer requirement.
Do not skip
Limitations and exclusions
- Do not apply PERC to create low pretest probability or to an unselected population.
- A positive criterion does not diagnose PE.
- Not validated for every pediatric, pregnant, postpartum, or other special population.
- Measurement method, clinical stability, and local pathway requirements remain controlling.
One clearly labeled, contextually relevant sponsor may support this reference area. Sponsorship will never interrupt inputs, obscure results, influence formulas, or imply clinical endorsement.
About this tool
PERC Rule Calculator for Pulmonary Embolism
Use this PERC calculator only after an appropriate clinician has established a low pretest probability for pulmonary embolism.
All eight criteria must be negative to produce a PERC-negative result. A positive criterion does not diagnose PE and requires the applicable diagnostic pathway.