Estimate the pre-test probability of Deep Vein Thrombosis (DVT) and Pulmonary Embolism (PE) using the validated Wells scoring system. This tool helps guide diagnostic testing decisions.
For Deep Vein Thrombosis (DVT) and Pulmonary Embolism (PE) Risk Assessment
Score: 0
Probability:
Recommendation:
The Wells' Score is a clinical prediction rule used to estimate the pre-test probability of venous thromboembolism, specifically Deep Vein Thrombosis (DVT) and Pulmonary Embolism (PE). Developed by Dr. Philip Wells, these scoring systems help clinicians determine the appropriate diagnostic approach for patients with suspected thromboembolism.
There are separate Wells scores for DVT and PE, each incorporating different clinical factors and risk elements. The scores help stratify patients into low, moderate, or high probability categories, which then guide decisions about D-dimer testing, imaging studies, and treatment initiation.
These tools are particularly valuable in emergency departments and outpatient settings where rapid, evidence-based decision-making is crucial for patient safety and resource utilization.
Low Risk (≤0 points): 5% probability
D-dimer; if negative, DVT ruled out
Moderate Risk (1-2 points): 17% probability
D-dimer; if positive, ultrasound required
High Risk (≥3 points): 53% probability
Ultrasound required
Low Risk (<2 points): 1.3% probability
D-dimer; if negative, PE ruled out
Moderate Risk (2-6 points): 16.2% probability
D-dimer; if positive, CT-PA or V/Q scan
High Risk (>6 points): 40.6% probability
CT-PA or V/Q scan recommended
D-dimer is most useful in low and moderate probability patients. A negative D-dimer in low-risk patients effectively rules out VTE. In moderate-risk patients, a negative D-dimer significantly reduces the probability, while a positive result necessitates imaging.
High-risk patients typically require immediate imaging regardless of D-dimer results. For DVT, compression ultrasound is the first-line imaging. For PE, CT pulmonary angiogram (CT-PA) or ventilation-perfusion (V/Q) scan are appropriate options.
The Wells score should be used in conjunction with clinical judgment and institutional protocols. Consider patient factors such as pregnancy, contraindications to imaging, and bleeding risk when making treatment decisions.
A 45-year-old woman presents with left leg swelling and pain 2 weeks after a long flight. She has no history of cancer or recent surgery. On examination, her entire left leg is swollen with localized tenderness along the deep venous system.
✓ Entire leg swollen: +1 point
✓ Localized tenderness: +1 point
✗ Alternative diagnosis likely: 0 points
DVT Wells Score: 2 points
Moderate risk (17%) - Obtain D-dimer; if positive, perform ultrasound
A 62-year-old man with lung cancer presents with sudden onset shortness of breath and chest pain. His heart rate is 110 bpm. He has clinical signs of DVT in his right leg, and PE is considered the most likely diagnosis.
✓ Clinical signs of DVT: +3 points
✓ PE most likely diagnosis: +3 points
✓ Heart rate >100: +1.5 points
✓ Active malignancy: +1 point
PE Wells Score: 8.5 points
High risk (40.6%) - Proceed directly to CT-PA or V/Q scan
Cardiology, Electrophysiology
Dr. Eleanor Vance is a board-certified cardiologist with over 15 years of experience specializing in cardiac electrophysiology and the management of atrial fibrillation. After graduating summa cum laude from Johns Hopkins School of Medicine, she completed her residency at Massachusetts General Hospital and a fellowship in cardiology at the Cleveland Clinic.
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