Wells DVT Score Calculator
The Wells DVT criteria provide a validated pre-test probability estimate for deep vein thrombosis in patients presenting with leg symptoms. The score ranges from -2 to 9. A score of 0 or below indicates low probability (approximately 3% prevalence of DVT), 1-2 indicates moderate probability (approximately 17%), and 3 or above indicates high probability (approximately 75%). The score is used together with D-dimer testing to guide further imaging. In low and moderate probability patients, a negative sensitive D-dimer can safely rule out DVT without ultrasound. High probability patients require compression ultrasonography regardless of D-dimer result. Select all criteria that apply to the patient.
Wells DVT score formula
Score = Sum of all positive criteria points - 2 (if alternative diagnosis as likely)
Low: 0 or below (~3% DVT prevalence)
Moderate: 1-2 (~17%)
High: 3 or above (~75%)
Each clinical criterion contributes 1 point, except the alternative diagnosis criterion which subtracts 2 points. A score can be negative if an alternative diagnosis is present along with few positive criteria.
Next steps by probability
- Low probability (score 0 or below): D-dimer test. If negative: DVT excluded. If positive: compression ultrasound.
- Moderate probability (score 1-2): D-dimer or direct ultrasound. Negative D-dimer (sensitive assay) can exclude DVT.
- High probability (score 3+): Compression ultrasound immediately. D-dimer is not useful to rule out at this probability.
Frequently asked questions
What is the Wells DVT score?
The Wells DVT score (Wells criteria for DVT) is a validated clinical decision rule that stratifies patients into low, moderate, or high pre-test probability of deep vein thrombosis. Developed by Philip Wells in 1997, it combines 9 clinical criteria to assign a score that guides the use of D-dimer testing and ultrasound imaging.
How are the Wells DVT categories defined?
Score of 3 or above: High probability of DVT (approximately 75% prevalence in studies). Score 1-2: Moderate probability (approximately 17%). Score 0 or below: Low probability (approximately 3%). D-dimer can be used to rule out DVT in low/moderate probability cases; high probability requires compression ultrasound regardless of D-dimer.
What are the Wells DVT criteria?
Active cancer (+1), paralysis/paresis/plaster immobilization of leg (+1), bedridden 3+ days or major surgery within 12 weeks (+1), localized tenderness along deep venous system (+1), entire leg swollen (+1), calf swelling 3+ cm greater than asymptomatic side (+1), pitting edema in symptomatic leg (+1), collateral superficial veins (+1), previously documented DVT (+1), alternative diagnosis at least as likely (-2).
When should I order a D-dimer vs ultrasound?
For low probability (score 0 or below): D-dimer first. If negative (below threshold), DVT is ruled out. If positive, proceed to ultrasound. For moderate probability (1-2): D-dimer or direct ultrasound depending on clinical context. For high probability (3+): Proceed directly to compression ultrasound; D-dimer is not useful to rule out DVT at high pre-test probability.
What is the difference between Wells DVT and Wells PE criteria?
They are separate scoring systems for different diagnoses. Wells DVT criteria estimate probability of deep vein thrombosis in the leg. Wells PE (pulmonary embolism) criteria estimate probability of PE in the pulmonary vasculature. While related (DVT can progress to PE), the two scores use different clinical variables.
Official sources
- CDC: Deep Vein Thrombosis (DVT) Facts.
- NIH National Heart, Lung, and Blood Institute: Deep Vein Thrombosis Overview.
Reviewed by the CalculatorHub team, edited by James Graham, 15 June 2026. See our methodology.