Version July 2025
CUS: compression ultrasonography; DVT: deep venous thrombosis; PTP: pretest probability.
* In our practice, we typically determine the probability of DVT using Wells or modified Wells criteria, although gestalt estimates are a reasonable alternative. Some clinicians skip this step and perform CUS in everyone.
¶ Start empiric anticoagulation if workup is delayed. Refer to related UpToDate content.
Δ High-sensitivity D-dimer assessment is sensitive (but not specific) for DVT. Low- and moderate-sensitivity D-dimer assays may not reliably exclude DVT in patients with moderate PTP.
◊ D-dimer level ≥500 ng/mL is not diagnostic of DVT and can be elevated in many other conditions (eg, infection, kidney failure).
§ Whole-leg CUS images both the proximal and calf veins while proximal vein CUS only images the proximal veins. Choosing between them may be institution-dependent. The inclusion of Doppler evaluation, which assesses venous flow, is not universal. Absent flow by Doppler supports the diagnostic finding of noncompressibility of the imaged vein on CUS.
¥ If ipsilateral recurrence is suspected, in the absence of a previous CUS for comparison, magnetic resonance direct thrombus imaging, if available, may be useful to distinguish old from new thrombus.
‡ If calf vein DVT is suspected, whole-leg CUS or repeat proximal CUS are reasonable. If iliac vein thrombosis is suspected (eg, entire leg swelling with or without abdominal, back, or buttock pain), Doppler ultrasound of the iliac vein is indicated; magnetic resonance venography is an alternative. Other imaging options include computed tomography venography.