Table 1: Clinical characteristics for predicting the pretest probability of deep venous thrombosis. The Wells score model demonstrates well-established criteria for assessment of suspected DVT [22, 23].

Wells score
Clinical characteristicsScore

Active cancer+1
Paralysis or plaster immobilisation+1
Bed rest >3 days or major surgery <4 weeks+1
Localised tenderness along the distribution of the deep venous system+1
Entire leg swollen+1
Calf swelling >3 cm when compared with asymptomatic leg+1
Pitting oedema+1
Collateral superficial veins (nonvaricose)+1
Previously documented deep vein thrombosis+1
Alternative diagnosis at least as likely as deep vein thrombosis−2

Clinical probability

Unlikely<2
Likely≥2