PERC rule
Background
- Pulmonary Embolism Rule-out Criteria — used to identify patients in whom pulmonary embolism can be excluded without D-dimer testing
- Only apply if clinical gestalt for PE is low (i.e., you would be confident PE is excluded with a negative D-dimer)
- If ALL 8 criteria are met in a low-risk patient, no further workup is needed (negative predictive value >99%)
Criteria
PERC Rule Calculator
Check all of the following that are true:
- Age <50yr
- Pulse ox >94% (room air)
- HR <100
- No prior PE or DVT
- No recent surgery or trauma (within prior 4wk)
- No hemoptysis
- No estrogen use
- No unilateral leg swelling
In patients with low suspicion for PE (best-guess pre-test probability <15%) AND all are true, only 0.9% had PE (n=7527) and it can be ruled-out without further testing (i.e. no need for d-dimer)[1][2]
Application
- Step 1: Assess clinical probability (gestalt or Wells criteria)
- Step 2: If low probability (Wells ≤4), apply PERC
- Step 3: If all PERC criteria met → stop workup; no D-dimer needed
- Step 4: If any PERC criterion NOT met → obtain D-dimer
- Do NOT apply PERC in moderate or high pre-test probability patients
Validation
- Validated on 8,138 patients across 13 EDs
- Missed PE rate when PERC-negative with low gestalt: <2% (below the testing threshold)
- No PE-related deaths in PERC-negative group at 45-day follow-up
See Also
References
- ↑ Kline JA, et al. Clinical criteria to prevent unnecessary diagnostic testing in emergency department patients with suspected pulmonary embolism. J Thromb Haemost 2004; 2: 1247–55.
- ↑ Kline JA, et al. Prospective multicenter evaluation of the pulmonary embolism rule-out criteria. J Thromb Haemost 2008; 6: 772–80. (PMID: 18318689).