Radiologic diagnoses of patients who received imaging for venous thromboembolism despite negative D-dimer tests.

Objective: The literature supports a negative D-dimer (-DD) excluding venous thromboembolic disease (VTE) in low-risk patients. We determined the radiologic diagnoses in patients where imaging was ordered despite a -DD.

Methods: This is a retrospective chart review of patients with a -DD (Tinaquant; Roche Diagnostics, Mannheim, Germany) and a radiologic study within 48 hours, sought to determine radiologic diagnosis (primary outcome), treatment of VTE, and consensus diagnosis of acute VTE.

Results: Among 3462 DD tests, 1678 met the inclusion criteria. Of 1362 patients with DD values of 350 ng/mL or less, 166 (12.2%) had radiologic studies: 93.4% of the final radiologic diagnoses were negative for VTE, 3.6% were indeterminate, and 3.0% (1.0%-6.9%) were positive; 1.8% ultimately had a consensus diagnosis of acute VTE. In 316 patients with DD values between 351 and 500 ng/mL, 88 (27.8%) had radiologic studies: 95.5% were negative, 1.1% were indeterminate, and 3.4% (0.7%-9.6%) were positive.

Conclusions: Of patients who receive radiologic studies despite -DD tests, 3.0% have positive radiologic diagnoses for acute VTE; only 1.8% had acute VTE after the review of their hospital course.