Table 1.

Pretest probability assessment (Wells score)

	Points
Active cancer (treatment ongoing or within previous 6 months or palliative)	1
Paralysis, paresis, or recent plaster immobilization of the lower extremities	1
Recently bedridden for 3 days or major surgery within 12 weeks requiring general or regional anesthesia	1
Localized tenderness along the distribution of the deep veins	1
Entire leg swollen	1
Calf swelling 3 cm > asymptomatic side (measured 10 cm below tibial tuberosity)	1
Pitting edema limited to the symptomatic leg	1
Collateral superficial veins (nonvaricose)	1
Previous DVT	1
Alternative diagnosis as likely as or more likely than DVT	−2

Notes: DVT unlikely: ≤1; DVT likely: ≥2