Do Emergency Physicians Use Serum d-Dimer Effectively to Determine the Need for CT When Evaluating Patients for Pulmonary Embolism? Review of 5,344 Consecutive Patients

OBJECTIVE. The purpose of our study was to investigate whether d-dimer screening is being used effectively to determine the need for MDCT in diagnosing acute pulmonary embolism (PE) in emergency department patients.MATERIALS AND METHODS. We performed a retrospective review of all patients who underwent d-dimer testing or MDCT in the emergency department from January 1, 2003, through October 31, 2005. A d-dimer value of > 0.43 μg/mL was considered positive. Diagnosis of PE was made on the basis of the MDCT. Clinical algorithms for diagnosing PE mandate that patients with a low clinical suspicion for PE undergo d-dimer testing, then MDCT if positive. For patients with a high clinical suspicion for PE, MDCT should be performed without d-dimer testing.RESULTS. Of 3,716 d-dimer tests, 1,431 (39%) were positive and 2,285 (61%) were negative. MDCT was performed in 166 (7%) patients with negative d-dimer results and in 826 (58%) patients with positive d-dimer results. The prevalence of PE in patients with a high ...