More importantly, the use of any rule is associated with reduction in recurrent thromboembolism.The Wells score:
clinically suspected DVT – 3.0 points
alternative diagnosis is less likely than PE – 3.0 points
tachycardia (heart rate > 100) – 1.5 points
immobilization (≥ 3d)/surgery in previous four weeks – 1.5 points
history of DVT or PE – 1.5 points
hemoptysis – 1.0 points
malignancy (with treatment within six months) or palliative – 1.0 pointsTraditional interpretation
Score >6.0 – High (probability 59% based on pooled data)
Score 2.0 to 6.0 – Moderate (probability 29% based on pooled data)
Score <2.0 – Low (probability 15% based on pooled data)Alternative interpretation
Score > 4 – PE likely. Consider diagnostic imaging. Score 4 or less – PE unlikely. Consider D-dimer to rule out PE.Recommendations for a diagnostic algorithm were published by the PIOPED investigators; however, these recommendations do not reflect research using 64 slice MDCT. These investigators recommended:

Low clinical probability. If negative D-dimer, PE is excluded. If positive D-dimer, obtain MDCT and base treatment on results. Moderate clinical probability. If negative D-dimer, PE is excluded. However, the authors were not concerned that a negative MDCT with negative D-dimer in this setting has a 5% probability of being false. Presumably, the 5% error rate will fall as 64 slice MDCT is more commonly used. If positive D-dimer, obtain MDCT and base treatment on results. High clinical probability. Proceed to MDCT. If positive, treat, if negative, more tests are needed to exclude PE. A D-dimer of less than 750 ug/L does not rule out PE in those who are at high risk.
It puts the subjects into one of five classes (I–V), with 30-day mortality ranging from 1.1% to 24.5%. Those in classes I and II are low-risk and those in classes III–V are high-risk. References
External links

Pulmonary embolism at Curlie
Wells criteria for pulmonary embolism online calculator Archived 2016-11-21 at the Wayback Machine
Clinical prediction website – Wells criteria for pulmonary embolism
 Media related to Pulmonary embolism at Wikimedia Commons
"Pulmonary Embolism". MedlinePlus. U.S. National Library of Medicine.