PERC Rule (PE rule-out)
PERC Rule (PE rule-out) - a deterministic tool in Sophie Well's Clinical Scoring & Risk group.
Open the PERC Rule (PE rule-out) → Runs in your browser. No signup, no tracking.
What this is
Check the eight-item Pulmonary Embolism Rule-out Criteria (Kline 2004): age <50, HR <100, SpO2 >=95% on room air, no hemoptysis, no exogenous estrogen, no prior DVT/PE, no recent surgery or trauma, and no unilateral leg swelling. If every criterion is satisfied in a patient who is already low pretest probability, PE can be ruled out without further workup.
When to use it
Apply PERC only after clinical gestalt or Wells has already established a low pretest probability for PE. PERC is a rule-out aid for that specific population - it is not a screening test, and a single failed criterion does not diagnose PE; it only means PERC cannot be used and the workup continues with D-dimer or imaging.
References
Kline JA, et al. PERC rule. J Thromb Haemost. 2004;2(8):1247-1255. Use only if clinical pretest probability is low.
Worked example: PERC 1 positive feature (age >= 50): rule-out does NOT apply.
Sophie Well is a reference and educational tool. Not medical, legal, or financial advice. Does not replace clinician judgment, professional billing review, or legal counsel.