The recommendations, based on a literature review and the best available evidence, include:

• Use validated prediction rules (e.g., Wells or Geneva tools) to estimate a patient’s pretest probability of acute PE.
• For patients with a low pretest probability who also meet all Pulmonary Embolism Rule-Out Criteria (PERC), neither D-dimer testing nor imaging should be performed. The PERC comprise eight variables (see link below).
• For patients with an intermediate pretest probability or those who do not meet all PERC, perform high-sensitivity D-dimer testing; imaging should not be done initially.
• For those over age 50, use age-adjusted D-dimer thresholds (instead of the usual 500 ng/mL) to decide whether to proceed to imaging; patients with a low-age-adjusted level should not undergo imaging.
• For patients with a high pretest probability of PE, forego D-dimer testing and go straight to computed tomographic pulmonary angiography. If CTPA is contraindicated or unavailable, ventilation-perfusion lung scanning may be used.