Wells Score for DVT Calculator

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Active cancer (treatment within 6 months, or palliative)

Paralysis, paresis, or recent cast immobilization of leg

Recently bedridden ≥3 days, or major surgery within 12 weeks

Localized tenderness along deep venous system

Entire leg swollen

Calf swelling >3 cm vs. asymptomatic leg

Pitting edema confined to symptomatic leg

Collateral superficial (non-varicose) veins

Previously documented DVT

Alternative diagnosis at least as likely as DVT (−2 points)

Results

Wells DVT Score

0

Low probability

Score	Interpretation (3-tier)
≥ 3	High probability of DVT
1 – 2	Moderate probability
≤ 0	Low probability

What is the Wells Score for DVT?

The Wells Score for deep vein thrombosis (DVT) is a validated clinical prediction rule that estimates the pretest probability that a patient with leg symptoms has a deep vein thrombosis. Developed by Dr. Philip Wells and colleagues, it combines ten readily available clinical findings into a single weighted point total used to guide further testing such as D-dimer assays and compression ultrasonography.

Common clinical signs assessed in the Wells DVT criteria, such as calf swelling and localized tenderness along the deep veins.

How to use this calculator

Tick each clinical criterion that applies to your patient. Nine criteria each add +1 point. The final criterion — "an alternative diagnosis is at least as likely as DVT" — subtracts 2 points. The calculator sums the points instantly and returns the total along with a three-tier risk band: low (≤0), moderate (1–2), or high (≥3) probability of DVT.

The formula explained

$$\text{Score} = \text{(active cancer)} + \text{(paralysis/cast)} + \text{(bedridden/recent surgery)} + \text{(deep vein tenderness)} + \text{(entire leg swollen)} + \text{(calf swelling} > 3\text{ cm)} + \text{(pitting edema)} + \text{(collateral superficial veins)} + \text{(previous DVT)} - 2 \times \text{(alternative diagnosis as likely)}$$ Each positive item is worth 1 point except the alternative-diagnosis item, which is −2.

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Total Wells score stratifies patients into low, moderate, or high pretest probability of DVT.

Worked example

A patient has active cancer (+1), localized deep-vein tenderness (+1), an entire swollen leg (+1), and calf swelling greater than 3 cm (+1), with no alternative diagnosis. Total = $$1 + 1 + 1 + 1 = \mathbf{4},$$ placing them in the high-probability category, where proceeding directly to ultrasound is often recommended.

FAQ

Is this a diagnosis? No. The Wells Score estimates probability only and must be combined with D-dimer testing and/or imaging and clinical judgment.

What is the two-tier version? Some protocols use ≥2 = "DVT likely" and <2 = "DVT unlikely." This tool uses the three-tier (low/moderate/high) cutoffs.

Can the score be negative? Yes. If the alternative-diagnosis criterion is selected with few or no other points, the total can be −2, indicating low probability.