Pretest probability of lower-extremity deep vein thrombosis using 9 clinical Wells criteria. Output: low, moderate, or high DVT probability – guides D-dimer and venous ultrasound decisions.
The Wells DVT score is a prehospital and emergency department clinical tool for assessing lower-extremity deep vein thrombosis, developed by P.S. Wells in 1997. Used in primary care, outpatient surgery, and emergency medicine. Components (1 point each): active cancer, paralysis/paresis/immobilization, bedrest >3 days or major surgery within 12 weeks, localized tenderness along deep veins, entire leg swelling, unilateral calf swelling >3 cm vs asymptomatic side, pitting edema, distended superficial collaterals, prior DVT; –2 points if an alternative diagnosis is more likely than DVT. Interpretation: 0 – low probability (3–5%), 1–2 – moderate (17%), ≥3 – high (53–75%). Low probability allows D-dimer rule-out; moderate and high require duplex ultrasound. The score is less accurate in hospitalized and cancer patients, where direct ultrasound is preferred.
Formula version: wells-2003-v1
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