clinical probability of DVT

Last edited 04/2018 and last reviewed 05/2023

The clinical diagnosis of DVT is generally thought to be unreliable. However, Wells et al. suggest a well-validated clinical prediction rule which could be used to estimate the pretest probability.

  • the original version classified patients into low, moderate or high risk, based on the presence or absence of clinical criteria
  • in the revised Wells scoring system, the risk categories were trimmed to “unlikely” or “likely” (1,2).

The revised Wells score or criteria for assessment of suspected DVT is mentioned below (with a possible score of -2 to 9):


Factor

Points

active cancer (treatment within last six months or palliative)

1

calf swelling ≥3 cm compared to asymptomatic calf (measured 10 cm below tibial tuberosity)  

1

collateral superficial veins (non-varicose) 

1

pitting oedema (confined to symptomatic leg) 

1

swelling of entire leg

1

localised tenderness along distribution of deep venous system 

1

paralysis, paresis, or recent cast immobilisation of lower extremities

1

recently bedridden ≥3 days, or major surgery requiring regional or general anesthetic in the previous 12 weeks 

1

previously documented deep-vein thrombosis 

1

alternative diagnosis at least as likely as DVT

-2

Clinical probability simplified score 

  • DVT “likely” - 2 points or more
  • DVT is “unlikely” - 1 point or less (3)

The sensitivity for DVT of the Wells criteria is between 77–98% while the specificity is 38–58%. Therefore, it cannot be as the sole diagnostic modality for DVT (2)

Reference:

Related pages:

deep vein thrombosis

Wells score in the clinical prediction of pulmonary embolus (PE)

VTE PREDICT - predicting risk of recurrent venous thromboembolism (VTE)