Wells Pretest Probability Score
Strategy for assessing PE and DVT

Even with the high sensitivity and negative predictive value of D-dimer testing, the D-dimer assay cannot be used alone to exclude venous thromboembolism (VTE); it must be used in combination with a pretest probability scoring system. The Wells scoring system is commonly used to assess a patient’s risk of having either a PE or DVT based on a number of clinical features.

Wells Pretest Probability Model to Assess PE

Clinical signs and symptoms of DVT (objectively measured calf swelling or pain with palpation of deep vein region)3.0
An alternative diagnosis is less likely than PE3.0
Heart rate >100 beats per minute1.5
Immobilization or surgery in the previous 4 weeks1.5
Previous DVT or PE1.5
Malignancy (on treatment, treated in the past 6 months, or palliative care)1.0


Interpretation of Point Total

ScoreMean ProbabilityRisk
<2 points3.6Low
2 to 6 points20.5Moderate
>6 points66.7High


Wells Pretest Probability Model to Assess DVT

Active cancer (patient either receiving treatment for cancer within the previous 6 months or currently receiving palliative treatment)1.0
Paralysis, paresis, or recent case immobilization of the lower extremities1.0
Recently bedridden for ≥3 days, or major surgery within the previous 12 weeks requiring general or regional anesthesia1.0
Localized tenderness along the distribution of the deep venous system1.0
Entire leg swelling1.0
Calf swelling at least 3 cm larger than that on the asymptomatic side (measured 10 cm below tibial tuberosity)1.0
Pitting edema confined to the symptomatic leg1.0
Collateral superficial veins (non-varicose)1.0
Previously documented deep vein thrombosis1.0
Alternative diagnosis at least as likely as deep vein thrombosis-2.0


Interpretation of Point Total

Low probabilityModerate probabilityHigh probability
-2 - 01-23-8


Share this page:

Related Products, Services & Resources