A retrospective application of the pulmonary embolism rule out criteria (PERC) of the American College of Physicians would reduce the number of CTPAS by 6% without a false negative in an Irish hospital.

Background: Internationally, the number of computerised tomographic pulmonary angiographies (CTPAs) being performed to rule out pulmonary embolism (PE) has caused some concern.

Aim: This study was performed to assess if the application of Pulmonary Embolism Rule-out Criteria (PERC) in an Irish Emergency Department (ED) would have helped to safely reduce the number of D-dimer assays and computed tomographic pulmonary angiographies (CTPAs) ordered.

Methods: The PERC was retrospectively calculated in all patients who underwent CTPA for possible PE.