Clinical probability of DVT
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):
| 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:
- (1) Tovey C, Wyatt S. Diagnosis, investigation, and management of deep vein thrombosis. BMJ. 2003;326(7400):1180-4
- (2) Stone J et al. Deep vein thrombosis: pathogenesis, diagnosis, and medical management. Cardiovasc Diagn Ther. 2017;7(Suppl 3):S276-S284
- (3) National Institute for Health and Care Excellence (NICE) 2015. Venous thromboembolic diseases: diagnosis, management and thrombophilia testing
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