Wells score (deep vein thrombosis) calculator — interpretation & sources

Interpretation

≤ 1 — DVT unlikely	In the Wells 2003 strategy and AWMF 2023, D-dimer is the next step: a negative result excludes DVT without ultrasound; a positive D-dimer leads to compression ultrasound.
≥ 2 — DVT likely	In the Wells 2003 strategy and AWMF 2023, compression ultrasound is the next step; if negative, a negative D-dimer or repeat ultrasound after about a week completes the work-up.

What is the Wells score (deep vein thrombosis)?

The Wells DVT score estimates the probability of lower-limb deep vein thrombosis from nine clinical findings and one subtractive item. In the two-level form used by Wells and colleagues in a randomised management study (NEJM 2003), patients with ≤ 1 point (DVT unlikely) and a negative D-dimer could safely forgo ultrasound. It is the score used in the German AWMF S2k guideline.

When to use it

Outpatients or emergency patients with suspected first DVT of the leg.
Before ordering D-dimer, to decide whether a negative result can exclude DVT.
To prioritise compression ultrasound when access is limited.

When not to use it

Suspected upper-limb DVT.
Pregnancy and hospitalised patients, where performance is weaker.
Suspected recurrent DVT in the same leg without considering prior imaging.

How it is calculated

Criterion	Points
Active cancer (treatment ongoing, within 6 months, or palliative)	+1
Paralysis, paresis or recent plaster immobilisation of the leg	+1
Bedridden ≥ 3 days, or major surgery within 12 weeks (general or regional anaesthesia)	+1
Localised tenderness along the deep venous system	+1
Entire leg swollen	+1
Calf swelling ≥ 3 cm compared with the asymptomatic side	+1
Pitting oedema confined to the symptomatic leg	+1
Collateral superficial veins (non-varicose)	+1
Previously documented DVT	+1
Alternative diagnosis at least as likely as DVT	-2

Clinical pearls and limitations

Validated in outpatients with suspected first lower-limb DVT. It performs less well in inpatients, in suspected recurrence and in pregnancy. A three-level version (≤ 0 low, 1–2 moderate, ≥ 3 high) also exists — do not mix the two.
'Alternative diagnosis at least as likely' subtracts 2 points — the score can be negative.
Calf circumference is measured 10 cm below the tibial tuberosity and compared with the other leg.
Active cancer means treatment within 6 months, ongoing treatment, or palliative care.
In AWMF 2023, the two-level score: ≥ 2 high probability (DVT in about 28 %), ≤ 1 low (about 6 %).

Frequently asked questions

What Wells score means DVT is likely?

In the two-level version, 2 points or more = DVT likely; 1 point or less = DVT unlikely.

Can a low Wells score exclude DVT without ultrasound?

Only together with a negative D-dimer. In Wells 2003, the D-dimer strategy had a 3-month VTE rate of 0.4 % among patients in whom DVT had been ruled out.

What is the difference between Wells DVT and Wells PE?

They are separate scores with different items and cut-offs. Wells PE uses 1–3-point items and a cut-off of > 4; Wells DVT uses 1-point items and a cut-off of ≥ 2.

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Wells score (deep vein thrombosis)