WellsScore

Wells score, also known as the Wells criteria, is a widely used clinical prediction rule designed to estimate the pretest probability of venous thromboembolism, particularly deep vein thrombosis (DVT) and pulmonary embolism (PE). It was developed by Dr. Philip S. Wells and colleagues in the early 2000s and has since become a standard tool in emergency departments and other clinical settings to guide diagnostic testing.

There are separate Wells scoring systems for DVT and for PE. Both are point-based and derive their weight from patient history, physical examination findings, and selected risk factors. The DVT version includes factors such as active cancer, recent immobilization or surgery, leg swelling, localized tenderness along the deep venous system, and a history of DVT, among others, with an overall category that classifies patients into low, moderate, or high pretest probability. The PE version includes items such as clinical signs of DVT, history of prior DVT/PE, tachycardia, recent immobilization or surgery, hemoptysis, malignancy, and an assessment of whether PE is the more likely diagnosis, with its own low, intermediate, and high probability categories.

In practice, the Wells score guides the use of D-dimer testing and imaging studies. A low-probability category often allows safe exclusion of DVT or PE with a negative D-dimer, while higher-probability groups typically proceed to definitive imaging, such as duplex ultrasonography for DVT or CT pulmonary angiography for PE. The score is intended as a decision aid, not a stand-alone diagnosis, and its performance varies with population, prevalence, and concurrent testing. See also D-dimer and venous thromboembolism.