Diagnosis and Treatment of Deep Vein Thrombosis

Diagnostic Approach

The American College of Chest Physicians recommends assessing pretest probability using the Wells score or similar validated tool to categorize patients as low, moderate, or high probability 1, 2
Low probability patients have approximately 5% prevalence of DVT 1
Moderate probability patients have approximately 17% prevalence (95% CI: 13-23%) 2
High probability patients have approximately 53% prevalence (95% CI: 44-61%) 2
For low pretest probability patients, start with highly sensitive D-dimer testing rather than ultrasound 1, 3
If D-dimer is negative in low probability patients, no further testing is required - DVT is excluded 1, 2
For moderate pretest probability patients, begin with highly sensitive D-dimer as the preferred initial test 3
If D-dimer is negative in moderate probability patients, no further testing is needed 3
For high pretest probability patients, proceed directly to proximal CUS or whole-leg ultrasound - skip D-dimer testing 3, 2

In patients with suspected recurrent DVT, start with proximal CUS or highly sensitive D-dimer 4, 5
In pregnant patients, begin with proximal CUS - avoid D-dimer as initial test 4, 5
For upper extremity DVT, use combined modality ultrasound (compression with Doppler or color Doppler) 5

Essential baseline tests before initiating anticoagulation include complete blood count with platelet count, coagulation profile, and comprehensive metabolic panel to assess kidney and liver function 6
Do not delay treatment for additional imaging when DVT is already confirmed by appropriate ultrasound 6

The American College of Chest Physicians recommends that if proximal CUS is positive, treatment for DVT should be started immediately rather than obtaining confirmatory venography, in patients with suspected deep vein thrombosis 7, 8, 9
For patients with suspected deep vein thrombosis and a negative proximal CUS, additional testing with highly sensitive D-dimer, whole-leg US, or repeat proximal CUS in 1 week is recommended, according to the American College of Chest Physicians 7, 8, 9
If a single negative proximal CUS with negative highly sensitive D-dimer is found, no further testing is required, as stated by the American College of Chest Physicians 7, 8
In patients with extensive unexplained leg swelling despite negative proximal ultrasound, imaging the iliac veins to exclude isolated iliac DVT is recommended by the American College of Chest Physicians 9

For patients with isolated distal DVT detected on whole-leg US, serial testing to rule out proximal extension rather than immediate treatment is recommended, according to the American College of Chest Physicians 8, 9
The American College of Chest Physicians suggests that CT venography, MR venography, or MR direct thrombus imaging can be used as alternatives when ultrasound is impractical 7, 8
The American College of Chest Physicians recommends against routinely using CT venography or MRI in patients with suspected first lower extremity DVT 8