Wells Rule and d-Dimer Testing to Rule Out Pulmonary Embolism

7,268 patients with suspected pulmonary embolism from 6 prospective studies, including subgroups of inpatients, persons with cancer, chronic obstructive pulmonary disease, previous venous thromboembolism, delayed presentation, and age 75 years or older.

Age-adjusted d-dimer testing (age × 10 µg/L in patients aged >50 years) combined with a 'PE-unlikely' Wells score

Fixed d-dimer testing (≤500 µg/L) combined with a 'PE-unlikely' Wells score

Efficiency (proportion of patients in whom imaging could be withheld) and failure rate (3-month incidence of symptomatic venous thromboembolism)safety