Wells Clinical Prediction Score for DVT

Active cancer (treatment ongoing, administered within 6 months or palliative)+1
Paralysis, paresis or recent plaster immobilization of the lower extremities+1
Recently bedridden for >3 d or major surgery <12 wk+1
Localized tenderness along the distribution of the deep venous system+1
Swelling of entire leg+1
Calf swelling >3 cm larger than asymptomatic side (10cm below tibial tuberosity)+1
Pitting oedema confined to the symptomatic leg+1
Collateral superficial veins (nonvaricose)+1
Previously documented DVT+1
Alternative diagnosis at least as likely as DVT-2
High probability (PPV 53%)>=3
Moderate probability (PPV 17%)1 or 2
Low probability (PPV 5%)<=0

Wells PS, Anderson DR, et al.
Excluding pulmonary embolism at the bedside without diagnostic imaging: Management of patients with suspected pulmonary embolism presenting to the emergency department by using a simple clinical model and D-dimer.
Annals Intern Med 2001;135:98-107.

Wells PS, Owen C, Doucette S, Fergusson D, Tran H.
Does this patient have deep vein thrombosis?
JAMA. 2006 Jan 11;295(2):199-207.