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Wells' Criteria for Pulmonary Embolism Calculator
The Wells’ criteria for PE calculator is a clinical decision-making tool designed to assess the probability of pulmonary embolism (PE) in patients presenting with symptoms suggestive of this potentially life-threatening condition. A PE occurs when a blood clot, usually originating from a deep vein thrombosis (DVT) in the legs or pelvis, travels to the lungs and obstructs pulmonary blood flow. Timely diagnosis and intervention are essential to reduce the risk of complications or death.
This calculator applies the Wells’ score for PE, a set of clinical parameters developed by Dr. Phil Wells and colleagues in 1998. It is widely used by healthcare professionals to stratify patients into risk categories based on the likelihood of PE.
To use the Wells’ score PE calculator, clinicians enter patient-specific data such as signs and symptoms of DVT, elevated heart rate, recent surgery or immobilization, and hemoptysis. The calculator assigns a point value to each criterion, and the total Wells’ score for PE determines the risk category: low, moderate, or high probability.
Depending on the score, clinicians may proceed with additional diagnostic steps such as D-dimer testing, CT pulmonary angiography (CTPA), or ventilation-perfusion (V/Q) scanning to confirm or exclude PE. The Wells’ criteria PE calculator supports efficient triage and workup, promoting faster, more informed clinical decision-making and optimizing patient care.
Wells' Criteria for Pulmonary Embolism Calculator
Clinical signs and symptoms of DVT
PE is #1 diagnosis OR equally likely
Heart rate > 100
Immobilization at least 3 days or surgery in the previous 4 weeks
Previous, objectively diagnosed PE or DVT
Hemoptysis
Malignancy with treatment within 6 months or palliative
Value
Alternative diagnosis to DVT as likely or more likely
Alternative diagnosis to DVT as likely or more likely
How to Use the Wells’ Criteria PE Calculator & Interpret Results
To use the calculator, select all applicable Wells’ score PE criteria. The tool automatically sums the total Wells’ score for PE and classifies the patient into a corresponding risk category.
The Wells' Criteria for PE include:
• Clinical signs and symptoms of DVT (3 points)
• PE is #1 diagnosis OR equally likely (3 points)
• Heart rate > 100 bpm (1.5 points)
• Immobilization at least 3 days or surgery in the previous 4 weeks (1.5 points)
• Previous, objectively diagnosed PE or DVT (1.5 points)
• Hemoptysis (1 point)
• Malignancy with treatment within 6 months or palliative (1 point)
Three-tier model scoring interpretation:
• Low Risk (0–1 points): ~1.3% estimated PE probability. Consider D-dimer testing to rule out PE; no imaging needed if negative.
• Moderate Risk (2–6 points): ~16.2% estimated PE probability. Proceed with D-dimer or imaging based on clinical context.
• High Risk (≥7 points): ~37.5% estimated PE probability. Immediate imaging recommended (e.g., CT pulmonary angiography).
Two-tier model scoring interpretation:
• PE Unlikely (≤4 points): ~3% incidence of PE. Recommend D-dimer testing.
• PE Likely (>4 points): ~28% incidence of PE. Proceed directly to CTPA.
he Wells’ criteria PE calculator helps streamline diagnostic decision-making and reduce unnecessary imaging when combined with D-dimer results.
Clinical Considerations & Best Practices for Using the Wells’ Criteria PE Tool
The Wells’ criteria for PE is particularly useful in ambulatory or emergency settings where rapid risk stratification is required. When combined with D-dimer testing, the Wells’ score PE calculator can help rule out PE in low-risk patients without imaging, supporting more efficient and cost-conscious care.
However, it is important to use the Wells’ criteria PE tool within the context of the overall clinical assessment. The score includes subjective components, such as determining whether PE is the most likely diagnosis, which can vary between clinicians. In hospitalized or higher-risk populations, the pretest probability for PE may already be elevated, reducing the utility of the scoring system alone.
For best results:
• Use with age-adjusted D-dimer thresholds when applicable.
• Reevaluate scoring if the patient develops new or evolving symptoms.
• Clearly document clinical judgment when applying subjective criteria such as “PE most likely.”
Learn more on the BackTable VI Podcast
BackTable is a knowledge resource for physicians by physicians. Get practical advice on the Wells' Criteria for Pulmonary Embolism Calculator and how to build your practice by listening to the BackTable Podcast.
References
[1] Wells, P. S., et al. "Excluding pulmonary embolism at the bedside without diagnostic imaging: management of patients with suspected pulmonary embolism presenting to the emergency department by using a simple clinical model and D-dimer." Annals of Internal Medicine, 2001.
[2] Anderson, D. R., et al. "Accuracy of clinical assessment of deep-vein thrombosis." The Lancet, 2003.
[3] Wells, P. S., et al. "Evaluation of D-dimer in the diagnosis of suspected deep-vein thrombosis." New England Journal of Medicine, 2003.
Disclaimer: The Materials available on BackTable.com are for informational and educational purposes only and are not a substitute for the professional judgment of a healthcare professional in diagnosing and treating patients. The opinions expressed by participants of the BackTable Podcast belong solely to the participants, and do not necessarily reflect the views of BackTable.
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