Table 1.

Wells score for DVT clinical pretest probability

	Number of points	Proportion of patients	Prevalence of PE
Variables
Active cancer (treatment ongoing or within previous 6 mo or palliative)	1
Paralysis, paresis, or recent plaster immobilization of the lower extremities	1
Recently bedridden >3 d or major surgery within 4 wks	1
Localized tenderness along the distribution of the deep venous system	1
Entire leg swollen	1
Calf swelling 3 cm greater than on asymptomatic side (measured 10 cm below tibial tuberosity)	1
Pitting edema confined to the symptomatic leg	1
Dilated superficial veins (nonvaricose)	1
Previous documented DVT (or PE)	1
Alternative diagnosis as likely or greater than that of DVT	−2
Score interpretation
High probability*	≥3	10%	60%
Moderate probability*	1 or 2	30%	25%
Low probability†	≤0	60%	5%

^*A score of ≥2 has been termed “DVT likely.” This group makes up ∼40% of patients and has a prevalence of DVT of ∼33%.

^†A score of ≤1 has been termed “DVT unlikely.” This group makes up ∼75% of patients and has a prevalence of DVT of ∼10%. The original Wells DVT model was for a first suspected DVT and, therefore, did not include a score for previous VTE.