Wells Score for DVT Diagnosis



The Wells score for the diagnosis of a DVT.

The Wells score is the most widely used clinical decision tool for the diagnosis of deep vein thrombosis (DVT). This tool risk-stratifies patients into 'low', 'intermediate' and 'high' risk categories for DVT, based on a point system.

A score of less than two indicates low risk, and above two indicates intermediate/high risk.

Criteria Score
Active cancer (patient receiving treatment for cancer within 6 months or currently receiving palliative treatment). +1
Paralysis, paresis, or recent plaster or immobilisation of the lower extremeties. +1
Recently bedridden for 3 days or more, or major surgery within the previous 12 weeks requiring regional anaesthesia. +1
Localised tenderness along the distribution of the deep venous system. +1
Entire leg swollen. +1
Calf swelling at least 3cm larger than that on asymptomatic side (measured 10cm below tibial tuberosity). +1
Pitting oedema confied to the symptomatic leg. +1
Collateral superficial veins (non-varicose). +1
Previously documented deep vein thrombosis. +1
Alternative diagnosis at least as likely as deep vein thrombosis. -2

The tool assists the clinician in deciding if the patient requires a duplex ultrasound scan to exclude DVT. In patients with a Wells score of less than two, a whole blood D dimer assay should be performed to exclude a DVT safely.

If the D dimer assay is positive they will require a compression ultrasound. A score above two on the Wells score criteria also means the patient requires a compression ultrasound. If positive, treatment for DVT should be initiated.