Review the Pulmonary Embolism Rule-Out Criteria (PERC) and see whether all eight bedside criteria are absent in a low-risk worksheet setting.
The PERC (Pulmonary Embolism Rule-Out Criteria) rule is an 8-item bedside tool used in low-risk pulmonary embolism assessment. Developed by Kline et al. and later validated in emergency medicine studies, it is designed to identify the subset of patients whose overall profile is low enough that additional testing may be avoidable in some workflows.
This calculator keeps the eight criteria visible and simply shows whether the worksheet is all-negative or not. It does not determine a full PE workup on its own, and it should be interpreted only after low pre-test probability has already been established.
PERC is useful because it gives a structured yes/no checklist for a low-risk PE worksheet. It can help show whether the bedside criteria are fully absent rather than relying on memory or an informal impression.
That makes it most useful as a reference aid when discussing a low-risk presentation, not as a stand-alone imaging or treatment algorithm.
PERC Rule — 8 Binary Criteria (all must be absent for an all-negative worksheet): 1. Age ≥50 2. Heart rate ≥100 bpm 3. SpO2 <95% on room air 4. Hemoptysis 5. Estrogen use 6. Prior DVT or PE 7. Recent surgery or trauma 8. Unilateral leg swelling All absent = PERC negative Any present = PERC positive
Result: PERC Negative — all 8 criteria absent
A 38-year-old with chest pain but otherwise low-risk features has all 8 PERC criteria absent. In a true low pre-test probability setting, that pattern is the all-negative PERC profile commonly referenced in emergency medicine.
PERC is useful because it turns eight bedside yes/no items into a single all-negative or not-all-negative profile. That can help low-risk PE discussions stay structured instead of relying on memory alone.
The rule is intended only for already low-risk presentations. Outside that setting, the same eight criteria do not carry the same meaning, which is why this page should be treated as a worksheet and not as a stand-alone pathway engine.
The most common problems are applying PERC outside low-risk settings, overlooking estrogen exposure, or forgetting that a positive PERC result does not diagnose PE. The page is most useful when it is used simply to document which of the eight criteria are present.
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This calculator applies the eight Pulmonary Embolism Rule-Out Criteria exactly as a bedside exclusion rule, not as a stand-alone probability score. The page assumes the rule is being used only after the clinician has already judged the patient to have a low pre-test probability of PE. If all eight criteria are absent, the result is treated as PERC negative; if any criterion is present, the page directs the user back into the usual D-dimer or imaging pathway rather than claiming PE is likely.
The output should not be used in patients outside the rule's intended setting, such as moderate- or high-suspicion presentations, pregnancy, or inpatient populations. It is a structured way to avoid unnecessary D-dimer testing in carefully selected low-risk patients, not a replacement for the broader diagnostic algorithm.
If any PERC criterion is present, the worksheet is PERC positive. That does not diagnose PE; it only means the case no longer fits an all-negative PERC profile.
Pregnancy has separate physiologic considerations and is generally discussed using different diagnostic frameworks. This worksheet should not be treated as a stand-alone pregnancy pathway.
It means the broader clinical picture already suggests a low likelihood of PE before PERC is applied. PERC is intended only in that low-risk setting.
Wells and Geneva are broader pre-test probability tools, while PERC is an all-or-none bedside checklist intended for already low-risk settings.
No. It is best used as a bedside reference aid after low pre-test probability has already been established. The broader workup still depends on the full clinical context.