From the Guidelines
The Wells score is a clinical prediction tool used to assess the probability of deep vein thrombosis (DVT) by evaluating factors such as active cancer, paralysis or recent cast, recent immobilization or surgery, localized tenderness along deep veins, entire leg swelling, calf swelling, pitting edema, collateral superficial veins, and alternative diagnoses, with a score of ≥2 indicating a likely probability of DVT and a score of <2 indicating an unlikely probability of DVT 1.
Key Components of the Wells Score
The Wells score for DVT assessment includes the following factors:
- Active cancer (patient receiving treatment for cancer within the previous 6 months or currently receiving palliative treatment)
- Paralysis, paresis, or recent plaster immobilization of the lower extremities
- Recently bedridden for ≥3 days, or major surgery within the previous 12 weeks requiring general or regional anesthesia
- Localized tenderness along the distribution of the deep venous system
- Entire leg swollen
- Calf swelling at least 3 cm larger than the asymptomatic side (measured 10 cm below the tibial tuberosity)
- Pitting edema confined to the symptomatic leg
- Collateral superficial veins (nonvaricose)
- Previously documented deep venous thrombosis
- Alternative diagnosis at least as likely as deep venous thrombosis (assigned a score of -2)
Clinical Application of the Wells Score
The Wells score helps clinicians determine which patients require further diagnostic testing like D-dimer or imaging studies, improving clinical decision-making by identifying patients who truly need additional testing while reducing unnecessary procedures for low-risk individuals, ultimately leading to more efficient use of healthcare resources and better patient care 1.
Limitations and Considerations
While the Wells score is a useful tool for assessing the probability of DVT, it has limitations, including interobserver reliability and performance in primary care settings 1. Additionally, the score should be used in conjunction with clinical judgment and other diagnostic tests to confirm or rule out DVT.
From the Research
Overview of the Wells Score
The Wells score is a widely used prediction rule for pre-test probability assessment of deep vein thrombosis (DVT) 2, 3, 4, 5, 6. It is used to estimate the clinical probability of DVT in patients with suspected DVT.
Components of the Wells Score
The Wells score consists of several clinical criteria, including:
- Clinical symptoms and signs of DVT
- Risk factors for DVT, such as recent surgery or immobilization
- Alternative diagnoses that may mimic DVT
Classification of DVT Probability
The Wells score classifies patients into three categories of DVT probability:
- Low probability: patients with a low score are unlikely to have DVT
- Intermediate probability: patients with a moderate score may have DVT, but further testing is needed to confirm the diagnosis
- High probability: patients with a high score are likely to have DVT and require prompt treatment
Accuracy of the Wells Score
Studies have shown that the Wells score has a high degree of accuracy in assessing the probability of DVT 5. The score has been validated in various patient populations, including outpatients and inpatients 2, 3, 4, 6.
Comparison with Empirical Assessment
Some studies have compared the Wells score with empirical assessment, which is a clinical evaluation based on a predefined list of items that can be weighted individually 3, 6. The results show that both methods have similar accuracy, but empirical assessment may perform slightly better in categorizing patients in the high probability class.
Clinical Application
The Wells score is a useful tool in clinical practice for assessing the probability of DVT in patients with suspected DVT. It can help guide further testing and treatment decisions, and has been shown to be effective in reducing the number of unnecessary tests and improving patient outcomes 2, 3, 4, 5, 6.
Key Findings
- The Wells score is a widely used prediction rule for pre-test probability assessment of DVT 2, 3, 4, 5, 6
- The score classifies patients into three categories of DVT probability: low, intermediate, and high 2, 3, 4, 5, 6
- The Wells score has a high degree of accuracy in assessing the probability of DVT 5
- Empirical assessment may perform slightly better in categorizing patients in the high probability class 3, 6