PERC no-testing rule-out strategy,
does it really help with Noninferior exclusion of three-month missed thromboembolism in very-low-risk emergency patients?
research showsThe grade is B with 72 points. In the primary analyzable population, missed symptomatic thromboembolism occurred in 1/847 (0.1%) versus 0/902, an absolute difference of 0.1 percentage points with a one-sided 95% upper bound of 0.8%, within the prespecified 1.5% margin. This is conditional de-testing evidence, not evidence that D-dimer testing is harmful.
ads claimDirect use is limited to clinician-estimated PE probability below 15% plus all eight negative criteria: age under 50, pulse under 100, oxygen saturation at least 95%, no unilateral leg swelling, no hemoptysis, no recent trauma or surgery, no prior PE or DVT, and no exogenous estrogen.
Useful facts when choosing a product
- CT pulmonary angiography fell from 23% to 13%, an absolute 9.7-point reduction.
- Median emergency stay was 36 minutes shorter: 4 h 36 min versus 5 h 14 min.
- Admission fell from 16% to 13%, an absolute 3.3-point reduction.
What the research actually shows
Fourteen French emergency departments underwent cluster-randomized crossover assignment to two six-month strategy sequences. In a cluster trial, concealment concerns hiding each emergency department's period sequence before recruitment and selection, not individual patient envelopes. A computer-generated block sequence was combined with a blinded numbered center list. Clinicians necessarily knew the strategy after a period began, while consecutive eligibility and blinded independent event adjudication reduced selection and outcome bias. Limitation: noninferiority design. Listed item: noninferiority design. Avoidability: impossible - the de-testing question asks whether omission stays within an acceptable safety margin. Substantial attrition (>=15%) was 60/1916 (3.1%), so it does not apply. The French Ministry of Health PHRC 2014 program funded the AP-HP-sponsored trial; author industry relationships were reported outside this work.
Why this is classified as B (72)
A hard three-month event, public independence, and a met prespecified margin are balanced against one RCT and noninferiority-design bias, giving B with 72 points.
Counterpoint. Do not extend this result to PERC-positive patients or clinician-estimated PE probability of 15% or more.
Rejudgment record. New verdict — Hard three-month event, public funding, met 1.5% margin, and cluster crossover noninferiority design
| Endpoint | H | Hard endpoint - actual events such as death |
| Replication | R1 | Single confirmatory trial |
| Independence | I2 | Decisive evidence is publicly or non-profit funded |
| Effect size | E+ | Meets the clinically important threshold |
The scoring table and the verdict agree (B).
Sub-claim grades by effect
This ingredient is marketed for several effects. A single overall grade blends strong and weak claims together, so each effect is graded separately here. The overall grade reflects the strongest disconfirming or core claim.
| Effect (sub-claim) | Grade | Basis |
|---|---|---|
| Three-month de-testing safety in very-low-risk PERC-negative patients | B | The primary-analysis upper bound was 0.8%, within the 1.5% margin. |
| Reduced testing and emergency resource use | B | CT use, emergency stay, and admission decreased. |
Cross-check — Codex and Claude
Evidence Table
| Study | Design | Sample | Funding | Endpoint | Result | Weight |
|---|---|---|---|---|---|---|
| Study 1 | Cluster-randomized crossover noninferiority trial in 14 French emergency departments | 902 | French Ministry of Health PHRC 2014; AP-HP sponsor | Symptomatic thromboembolic event within three months missed at the inclusion visit | 0.1% vs 0%; absolute difference 0.1 points, one-sided 95% upper bound 0.8%; margin 1.5% | Pivotal hard-event noninferiority RCT |
Receipt — 1 References
All 1 cited sources were verified for existence at the original page (as of 2026-08-18).
Reviewed and approved: Chamgap Editorial Team · Approval date: 2026-08-18 · Corrections: none
Cite this verdict
[Chamgap] PERC No-Testing Rule-Out Strategy for Three-Month Missed Thromboembolism in Very-Low-Risk Emergency Patients With Suspected Pulmonary Embolism — Benefit — Evidence Grade B·72. 1 cited sources checked. Source: https://chamgap.com/en/verdicts/heart/perc-no-testing-very-low-risk-suspected-pulmonary-embolism/ · CC BY 4.0CC BY 4.0 — free to use with attribution; do not distort grades, numbers, or verdict meaning.
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