Table 3c. The PERC score *.

Age <50 years

Pulse <100 beats/minute

Oxygen saturation >94%

Absence of unilateral leg swelling, hemoptysis, recent surgery/trauma, prior deep vein thrombosis (DVT)/pulmonary embolism (PE), and oral contraceptive use

*The PERC rule was designed to rule out acute PE in patients presenting to the emergency room without further testing. The eight variables are listed above. As a diagnostic test, low gestalt clinical suspicion for PE and PERC negative status has been shown to have a sensitivity of 97.4% (confidence interval [CI] 95.8% to 98.5%) and specificity of 21.9% (CI 21.0% to 22.9%) ^{34– 36}.