A 58-year-old woman admitted with hemiplegia from a stroke one week ago develops left calf pain. Findings: left calf circumference 4 cm greater than the right, pitting oedema confined to the symptomatic leg, dilated non-varicose superficial collateral veins, and no alternative diagnosis more likely than DVT. Using the Wells criteria, what is her pretest probability category?

• A Low probability, D-dimer testing alone is adequate
• B Moderate probability, D-dimer or ultrasound depending on local protocol
• C Probability cannot be assessed because recent stroke invalidates the score
• D High probability, proceed directly to proximal leg vein ultrasound ✓

Explanation

She scores 5 points: paresis of a recently immobilised leg (1), localised deep vein tenderness implied by calf pain along the venous system (1), entire leg swelling (1), calf swelling greater than 3 cm compared with the other leg (1), pitting oedema (1), plus collateral superficial veins (1), giving 6 total. Any score of 3 or above is high probability, where guidelines advise proceeding straight to proximal compression ultrasound rather than relying on C-dimer.

Reference: Schwartz's Principles of Surgery, 11th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.