Which of the following is included in the PERC rule to rule out the need for further imaging in suspected PE?

• A. Hormone/Estrogen use
• B. Age > 50
• C. DVT/PE history
• D. Oxygen saturation < 95%

Answer: (D)

The PERC rule helps decide when imaging for PE can be avoided in low-risk patients by requiring all eight criteria to be negative. Among the options, the factor that aligns with a PERC criterion is no prior DVT or PE. The rule also requires no estrogen use (absence of hormone estrogen use), age under 50, and oxygen saturation of at least 95%. The statement about oxygen saturation being less than 95% would actually disqualify the rule-out, since the criterion is saturation ≥ 95%. So the correct concept is that prior DVT/PE history is a PERC criterion (absence of such history would support ruling out PE without imaging), while the others either violate the rule (age > 50, use of estrogen) or represent the opposite of a criterion (O2 saturation < 95% instead of ≥ 95%).