MDCalc

Wells' Criteria for DVT

Calculates risk of DVT based on clinical criteria.

There are several versions of these criteria with minor variations across studies; this version, based on Wells 2003, is among the most widely validated.

Active cancer
Treatment or palliation within 6 months
Bedridden recently >3 days or major surgery within 12 weeks
Calf swelling >3 cm compared to the other leg
Measured 10 cm below tibial tuberosity
Collateral (nonvaricose) superficial veins present
Entire leg swollen
Localized tenderness along the deep venous system
Pitting edema, confined to symptomatic leg
Paralysis, paresis, or recent plaster immobilization of the lower extremity
Previously documented DVT
Alternative diagnosis to DVT as likely or more likely

Result:

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Advice
  • As with all clinical decision aids, this tool is meant to support clinical decision-making, not dictate management. 
  • Apply these criteria only after a detailed history and physical examination is performed.
  • Use only when DVT is being considered; if there is no clinical concern for DVT, risk stratification is unnecessary.
Management

Patients can be categorized as “DVT unlikely” and “DVT likely;” an additional “moderate risk” group can be added depending on the sensitivity of the D-dimer being used. 

Score ≤0:

  • DVT is unlikely (cited prevalence of 5%). 
  • Proceed to D-dimer testing.    
    • A negative moderate- or high-sensitivity D-dimer reduces post-test probability to <1%; no further imaging is required.
    • A positive D-dimer should prompt US testing. 
      • Negative US: Sufficient for DVT rule out.
      • Positive US: Consider anticoagulation for DVT.

Score 1–2: 

  • Moderate risk for DVT (pretest probability 17%). 
  • Proceed to high-sensitivity D-dimer testing (moderate-sensitivity assays are not sufficient).
    • Negative high-sensitivity D-dimer: Sufficiently rules out DVT (post-test probability <1%).
    • Positive high sensitivity D-dimer: Proceed to US testing. 
      • Negative US: Sufficient for ruling out DVT.
      • Positive US: Consider anticoagulation for DVT.

Score ≥3: 

  • DVT is likely (pretest probability 17%–53%).
  • Proceed directly to diagnostic US:
    • Positive US: Treat DVT.
    • Negative US: D-dimer testing can further risk-stratify patients.
      • Negative D-dimer: 
        • DVT is sufficiently ruled out.
        • Consider discharge.
      • Positive D-dimer: 
        • Still concerning for DVT. 
        • Repeat US should be performed within 1 week for re-evaluation. 

A note on US options: 

  • A negative whole-leg US (proximal + calf) usually rules out DVT without repeat imaging. 
  • A negative proximal US may require alternative imaging or repeat US in ~1 week if suspicion remains in moderate- to high-risk patients.
Critical Actions

  • Do not rely on the Wells’ Criteria alone to rule out DVT in high-risk patients or when clinical concern remains high.

  • Evaluate for concurrent pulmonary embolism symptoms (e.g., chest pain, dyspnea) that may require urgent escalation in workup and management; decision aids, such as the Wells’ Criteria for PE or PERC Rule, should be considered.

  • Before starting anticoagulation, assess bleeding risk and contraindications; consider applying the RIETE Score.

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