How-to · Education only · Updated August 9, 2026
What is the Wells score for DVT?
Direct answer
The Wells score DVT estimates pretest probability of lower-extremity deep vein thrombosis before imaging. Sum nine clinical items (range −2 to +9): eight findings are +1 each; an alternative diagnosis at least as likely as DVT is −2. Teaching cutoffs: ≤0 low (~5% DVT in derivation cohorts), 1–2 moderate (~17–28%), ≥3 high (~53–75%). Not a diagnosis — pair with D-dimer and/or compression ultrasound per guideline.
Wells score DVT
Nine criteria and points from Wells PS et al. Lancet. 1997;350:1795-1798.
| Criterion | Points |
|---|---|
| Active cancer (treatment ongoing, within 6 months, or palliative) | +1 |
| Paralysis, paresis, or recent plaster immobilization of the lower extremity | +1 |
| Recently bedridden >3 days or major surgery within 4 weeks requiring general or regional anesthesia | +1 |
| Localized tenderness along the deep venous system | +1 |
| Swollen entire leg | +1 |
| Calf swelling >3 cm compared to the asymptomatic leg (measured 10 cm below tibial tuberosity) | +1 |
| Pitting edema confined to the symptomatic leg | +1 |
| Collateral superficial veins (non-varicose) | +1 |
| Alternative diagnosis at least as likely as DVT | -2 |
How is the Wells DVT score interpreted?
| Score | Category | Approx. prevalence | Typical pathway |
|---|---|---|---|
| ≤ 0 | Low clinical probability | ~5% DVT in derivation cohorts | Often D-dimer if assay available; imaging if still concerned |
| 1 – 2 | Moderate clinical probability | ~17–28% DVT in validation studies | D-dimer ± compression ultrasound per local algorithm |
| ≥ 3 | High clinical probability | ~53–75% DVT in validation studies | Proceed to venous ultrasound in most pathways |
Worked example (citeable)
Localized deep-vein tenderness (+1) + calf swelling >3 cm (+1) + pitting edema (+1) = Wells score 2 → Moderate clinical probability. Pretest probability ~17–28% in many studies. D-dimer and/or imaging decisions depend on assay sensitivity and local algorithm (including age-adjusted D-dimer).
- Localized tenderness along the deep venous system: +1
- Calf swelling >3 cm compared to the asymptomatic leg (measured 10 cm below tibial tuberosity): +1
- Total Wells DVT score = 2
- Category: Moderate clinical probability
Wells score DVT vs PE
| Aspect | DVT rule | PE rule |
|---|---|---|
| Clinical question | Suspected lower-extremity deep vein thrombosis | Suspected pulmonary embolism |
| Key positive items | Leg swelling, calf asymmetry >3 cm, deep-vein tenderness, edema, collateral veins | Clinical signs of DVT, PE more likely than alternatives, hemoptysis, immobilization/surgery |
| Negative / modifier item | Alternative diagnosis at least as likely (−2 points) | PE-specific Wells items — not the DVT −2 rule |
| Typical score range | −2 to +9 (nine DVT criteria) | Separate Wells PE score (different points) — do not interchange |
| Common teaching cutoffs | ≤0 low · 1–2 moderate · ≥3 high | Three-tier or two-tier (unlikely/likely) PE models — different thresholds |
| Primary next test | Compression ultrasound ± D-dimer | CT pulmonary angiography ± D-dimer |
Use the free Wells DVT calculator
Interactive checklist with automatic total and probability band: Wells DVT score calculator. Related: CHA₂DS₂-VASc score guide.
Education only — not medical advice. Primary source: Wells PS, Anderson DR, Bormanis J, et al.. Value of assessment of pretest probability of deep-vein thrombosis in clinical management. Lancet. 1997;350:1795–1798 (PMID 9428252). Follow ACCP, NICE, or your institutional VTE pathway.