About the Wells Score Calculator for Pulmonary Embolism
The Wells score is a clinical prediction rule that turns seven bedside findings into a pretest probability of pulmonary embolism (PE). It does not diagnose PE on its own; it estimates how likely PE is before further testing, which then guides whether the next step is a D-dimer blood test or direct imaging.
How the score is built
- Clinical signs and symptoms of DVT (leg swelling with pain on palpation of the deep veins): 3 points.
- PE is the number-one diagnosis, or equally likely as an alternative: 3 points.
- Heart rate above 100 beats per minute: 1.5 points.
- Immobilization for 3 or more days, or surgery in the previous 4 weeks: 1.5 points.
- Previous, objectively diagnosed DVT or PE: 1.5 points.
- Hemoptysis (coughing up blood): 1 point.
- Active malignancy (treated within the last 6 months, or palliative): 1 point.
Adding every criterion that is present gives a total from 0 to 12.5 points.
Putting the result in context
Two interpretations are commonly used side by side. The original three-tier method reads a score under 2 as low probability, 2 to 6 as moderate probability, and above 6 as high probability. The simplified two-tier (dichotomized) method instead uses a single cut-off: 4 or below is "PE unlikely," where a negative D-dimer test can help rule PE out without imaging, while above 4 is "PE likely," where imaging such as CT pulmonary angiography is generally recommended directly rather than starting with D-dimer.
When to consult a professional
This tool performs the standard Wells point count for education and documentation. It is not a diagnosis and does not replace clinical judgment — the "PE is the most likely diagnosis" criterion in particular depends on the full clinical picture. Any decision about testing or treatment for suspected pulmonary embolism should be made with a licensed healthcare provider.