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.
|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.