Assess symptoms and risk factors
Check vital signs and oxygen saturation
Perform clinical probability scoring
Use D-dimer testing when appropriate
Order CT pulmonary angiography
Use ventilation-perfusion scan if CT is unsuitable
Perform lower-extremity venous ultrasound if needed
Obtain electrocardiogram
Obtain chest X-ray
Consider arterial blood gas testing
Use echocardiography in unstable patients
Confirm diagnosis with imaging and clinical correlation