🫁 PERC Rule (PE Rule-out Criteria)
UseRule out PE when clinical pre-test probability is already low.
StrataIf every criterion is negative, PE is excluded without D-dimer. Any positive criterion means PERC fails — con…
LimitsInvalid outside a truly low-probability population — do not use to ov… · Pregnancy and some special populations need local PE pathways, not PE… · Failsafe: any yes → stop PERC and pursue D-dimer/imaging as indicated.
SourceKline JA, et al. J Thromb Haemost 2008
This-shift next steps
After scoring: open the scene pack, peer scores, and the matching pathway. Local reference — no HIS write.
- Who it is for
- Adults with suspected acute PE when deciding whether to test further, and risk stratification after confirmation.
- Who it is not for
- PERC must not rule out PE when clinical probability is not already low. Confirmed PE does not return to PERC. PERC is not an atrial-fibrillation tool and not a treatment page.
- Formula and variables
- Wells PE and revised Geneva estimate clinical probability; the version stays as on this page. PERC is used only when probability is already low, to see whether testing can stop. BOVA is only for normal blood pressure. Hestia only answers outpatient eligibility. No new score.
- Result → next step
- This page only asks whether testing can stop when clinical probability is already low. All negative: stop further PE testing. Do not use this page if PE is confirmed or probability is not low. Duration is not hung here.No numeric dose until age, weight, renal function, and pregnancy are all known. Pregnancy is contraindication or caution only.
- Guideline
- 2019 ESC PE
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Methodology · worked example, guidelines & full notes
Only valid in low pre-test-probability patients.
When to use
Rule out PE when clinical pre-test probability is already low.
How it works
Eight criteria (age ≥ 50, HR ≥ 100, SpO₂ < 95%, haemoptysis, oestrogen, prior DVT/PE, unilateral leg swelling, surgery/trauma ≤ 4 weeks). If all are negative, PE is excluded.
Key points
- Only valid in low pre-test-probability patients.
- Any positive criterion means PERC fails — proceed with workup.
- Avoids unnecessary D-dimer testing.
References
Worked calculation
The values below come from this tool's own example placeholders and are computed server-side with the formula shown on this page, so the arithmetic can be checked quickly. It demonstrates how to substitute values only — it is not clinical advice and not a real case.
| Age ≥ 50 | No |
|---|---|
| Heart rate ≥ 100 | No |
| SpO₂ < 95% | No |
| Haemoptysis | No |
| Oestrogen use | No |
| Prior DVT/PE | No |
| Unilateral leg swelling | No |
| Surgery/trauma ≤ 4 weeks (needing hospitalisation) | No |
→PERCAll negative
- Interpretation：In a low pre-test-probability patient, PE can be excluded without D-dimer.
| Age ≥ 50 | Yes |
|---|---|
| Heart rate ≥ 100 | Yes |
| SpO₂ < 95% | Yes |
| Haemoptysis | Yes |
| Oestrogen use | Yes |
| Prior DVT/PE | Yes |
| Unilateral leg swelling | Yes |
| Surgery/trauma ≤ 4 weeks (needing hospitalisation) | Yes |
→PERC8 positive
- Interpretation：PERC not satisfied — proceed with D-dimer/imaging per pathway.
Verification & sources · governance
FAQ
Frequently asked questions
- Does PERC Rule (PE Rule-out Criteria) upload patient data? Where is it calculated?
- Calculation runs locally in the browser; inputs and results are not uploaded. For licensed clinicians only; interpret with history, investigations and local protocols — not a diagnosis or prescription.
- How is PERC Rule (PE Rule-out Criteria) calculated in practice? Can you show a worked example?
- Inputs: Age ≥ 50 No, Heart rate ≥ 100 No, SpO₂ < 95% No, Haemoptysis No, Oestrogen use No, Prior DVT/PE No, Unilateral leg swelling No, Surgery/trauma ≤ 4 weeks (needing hospitalisation) No → Result: PERC All negative（Interpretation: In a low pre-test-probability patient, PE can be excluded without D-dimer.） Inputs: Age ≥ 50 Yes, Heart rate ≥ 100 Yes, SpO₂ < 95% Yes, Haemoptysis Yes, Oestrogen use Yes, Prior DVT/PE Yes, Unilateral leg swelling Yes, Surgery/trauma ≤ 4 weeks (needing hospitalisation) Yes → Result: PERC 8 positive（Interpretation: PERC not satisfied — proceed with D-dimer/imaging per pathway.）