Scoring

Active cancer (treatment ongoing, within 6 months, or palliative)

Paralysis, paresis or recent plaster immobilisation of the lower extremities.

Recently bedridden for 3 days or more, or major surgery within 12 weeks requiring general or regional anaesthesia.

Localised tenderness along the distribution of the deep venous system.

Entire leg swollen.

Calf swelling at least 3cm larger than asymptomatic side.

Pitting oedema confined to the symptomatic leg.

Collateral superficial veins (non-varicose).

Previously documented DVT.

An alternative diagnosis is at least as likely as DVT