Pre-Test Probability for Deep Vein Thrombosis
Stratifies the clinical pre-test probability of proximal lower limb DVT to guide D-dimer testing and compression ultrasonography. Score ranges from −2 to +9. Note: the alternative diagnosis criterion subtracts 2 points.
Check all that apply. Note: alternative diagnosis subtracts 2 points.
| +1 | Active cancer (treatment within 6 months or palliative) |
| +1 | Paralysis, paresis, or recent plaster immobilisation of lower extremity |
| +1 | Recently bedridden ≥3 days OR major surgery within 12 weeks under general or regional anaesthesia |
| +1 | Localised tenderness along the distribution of the deep venous system |
| +1 | Entire leg swollen |
| +1 | Calf swelling ≥3 cm greater than asymptomatic leg (measured 10 cm below tibial tuberosity) |
| +1 | Pitting oedema confined to the symptomatic leg |
| +1 | Collateral superficial veins (non-varicose) |
| +1 | Previously documented DVT |
| −2 | Alternative diagnosis at least as likely as DVT (e.g., cellulitis, muscle tear, Baker's cyst, chronic venous insufficiency) |
Score range: −2 to +9. The "alternative diagnosis" criterion is critical — it prevents over-investigation in patients with clear alternative explanations.
| Score | Probability | DVT Risk | Recommended Action |
|---|---|---|---|
| ≤0 | Low / DVT Unlikely | ~5% | High-sensitivity D-dimer. Negative D-dimer: DVT excluded. Positive D-dimer: proximal leg compression ultrasound (CUS). |
| 1–2 | Moderate Probability | ~17% | Proximal leg CUS. Positive: treat. Negative CUS: send D-dimer. Negative D-dimer: DVT excluded. Positive D-dimer: repeat CUS in 7 days. |
| ≥3 | High Probability | ~53% | Proximal leg CUS directly. If delay expected, start LMWH empirically. Positive CUS: treat. Negative CUS: consider further imaging (whole-leg US or venography). |