Wells Criteria for Pulmonary Embolism Calculator

Wells Criteria for Pulmonary Embolism

Select all criteria that apply to the patient

Clinical signs and symptoms of DVT

+3 points

Alternative diagnosis less likely than PE

+3 points

Heart rate > 100 beats per minute

+1.5 points

Immobilization (≥3 days) or surgery in the previous 4 weeks

+1.5 points

Previous DVT or PE

+1.5 points

Hemoptysis

+1 point

Malignancy (treatment within 6 months or palliative)

+1 point

What is the Wells Criteria for Pulmonary Embolism?

The Wells criteria is a clinical prediction rule used to estimate the pre-test probability of pulmonary embolism (PE) in patients suspected of having this condition. It helps clinicians determine which patients should undergo further diagnostic testing and what type of testing is most appropriate.

Developed by Dr. Philip Wells and colleagues, this scoring system uses clinical findings to stratify patients into different risk categories, guiding the diagnostic approach and potentially reducing unnecessary testing.

Clinical Significance

Pulmonary embolism is a potentially life-threatening condition that can be difficult to diagnose based on clinical presentation alone. The Wells score helps standardize the assessment of PE probability and guides the appropriate use of diagnostic resources.

When used in conjunction with D-dimer testing, the Wells criteria can safely rule out PE in low-risk patients, potentially avoiding unnecessary radiation exposure from CT pulmonary angiography.

Interpretation of Results

Traditional Three-Tier Model:

Low Risk (score < 2): ~3% probability of PE
Moderate Risk (score 2-6): ~28% probability of PE
High Risk (score > 6): ~78% probability of PE

Two-Tier Model (PE Unlikely/Likely):

PE Unlikely (score ≤ 4): ~12% probability of PE
PE Likely (score > 4): ~37% probability of PE

Recommended Next Steps

Low Risk/PE Unlikely:

Check D-dimer level. If negative, PE can be safely ruled out. If positive, proceed to imaging (CT pulmonary angiography or ventilation-perfusion scan).

Moderate Risk:

Proceed to imaging studies. D-dimer testing may be considered but has lower utility in this group.

High Risk/PE Likely:

Proceed directly to imaging studies. Consider starting anticoagulation therapy while awaiting results if there are no contraindications.

Limitations

The criteria are subjective, particularly the item regarding alternative diagnosis likelihood
Not validated in pregnant patients or those with a history of PE
Should be used as a guide and not replace clinical judgment
Does not account for all risk factors for venous thromboembolism