The PERC rule can be helpful in … * Emergency departments to quickly assess the need for advanced diagnostic imaging. * Primary care settings for evaluating symptomatic patients when PE is considered in the differential diagnosis. * Situations where access to diagnostic imaging is limited or when avoiding radiation exposure is a priority.

• Not recommended for use in patients with high pre-test probability of pulmonary embolism.
• May not be applicable to populations not included in the validation studies, such as pregnant women.
• Not a substitute for clinical judgment.

The PERC rule has been validated through multiple studies and is endorsed by clinical guidelines for use in appropriate patient populations. It has been shown to reduce unnecessary diagnostic testing without missing a significant number of PE cases when used correctly.

See Clinical criteria to prevent unnecessary diagnostic testing in emergency department patients with suspected pulmonary embolism for the original paper and Prospective multicenter evaluation of the pulmonary embolism rule-out criteria for one of the papers that validated the PERC rule.

• The PERC rule is designed to be a cost-effective and time-saving tool in the appropriate patient population.
• It is a rule-out criterion, not a diagnostic tool; it should be used to support clinical judgment, not replace it.
• Continuous education and training on the use of the PERC rule are vital to ensure it is applied effectively and safely.