PERC Rule

PE rule-out criteria

Age

Heart rate > 100

O2 saturation < 95%

Unilateral leg swelling

Hemoptysis

Recent surgery or trauma (past 4 weeks)

Prior DVT or PE

Hormone use (oral contraceptives, HRT, estrogen)

Enter the patient's age to calculate

Evidence

Original publication

Kline JA, Mitchell AM, Kabrhel C, Richman PB, Courtney DM. Clinical criteria to prevent unnecessary diagnostic imaging and emergency department overcrowding in low risk patients with suspected pulmonary embolism.

Journal of Thrombosis and Haemostasis, 2004

Open source

Validation

Kline JA, Courtney DM, Kabrhel C, et al. Prospective multicenter evaluation of the pulmonary embolism rule-out criteria. In patients with a gestalt-low pretest probability, PERC-negative had a false-negative rate of ~1%.

Journal of Thrombosis and Haemostasis, 2008

Open source

Last reviewed: 2026-09

Report an error in this calculator

MedScore is an educational and clinical decision-support tool. It does not provide a diagnosis, a treatment, or a drug-dosing recommendation, and it does not replace clinical judgement or local guidelines. Confirm every result against the original source before acting on it. The treating clinician remains responsible for all decisions.