Wells’ Criteria for Deep Vein Thrombosis (DVT) is a validated clinical prediction tool designed to estimate the pretest probability of DVT in patients with suspected venous thromboembolism. Developed by Dr. Philip Wells and colleagues in the 1990s, the score is based on clinical risk factors and examination findings such as leg swelling, tenderness along the deep venous system, and history of immobilization or prior DVT. It also incorporates the possibility of alternative diagnoses being more likely than DVT, which subtracts points from the total score.

The tool classifies patients into probability groups: low, moderate, or high, or into a simplified two-level model of “DVT unlikely” versus “DVT likely.” This stratification helps clinicians decide whether to order confirmatory tests such as D-dimer assays, venous duplex ultrasonography, or advanced imaging. For instance, in patients with a low Wells’ score and a negative D-dimer, DVT can often be excluded without the need for imaging. Conversely, in patients with a high score, imaging is prioritized regardless of D-dimer results.

Wells’ Criteria are widely adopted in emergency departments, hospital wards, and outpatient clinics as part of standardized venous thromboembolism workups. While the score improves efficiency and reduces unnecessary testing, it should always be used in conjunction with clinical judgment. Patient-specific variables such as age, comorbidities, anticoagulation status, or atypical presentations can affect its accuracy.