Table 2.

The PERC, if any one of the criteria is met then further investigation for PE is required

Age ≥ 50. Heart rate ≥100. Oxygen saturation on room air of <95%. Unilateral leg swelling. Haemoptysis. Recent trauma or surgery. Prior pulmonary embolism or deep vein thrombosis. Hormone use (oral contraceptives, hormone replacement or oestrogenic hormones use in males or female patients).

PE, pulmonary embolism; PERC, pulmonary embolism rule out criteria.

If none are present then PE can be excluded without further investigation if the patient is judged at low risk by the clinician.