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Wells' Criteria for Pulmonary Embolism

Risk stratify patients for acute Pulmonary Embolism (PE) and determine the necessity of high-sensitivity D-dimer testing versus immediate CT Pulmonary Angiography (CTPA).

Clinical Criteria

Select all that apply

Result

Wells' Score for PE

0.0points
Low Risk
1.3% Risk
Simplified Stratification
PE Unlikely
Recommendation: Consider D-dimer

Clinical Notes

  • Target Population: Patients with suspected Pulmonary Embolism (PE).
  • The Wells' criteria risk stratifies patients for acute PE and provides guidance for further testing (D-dimer vs CTA).
  • Should only be used after history and physical suggests PE is a diagnostic possibility.
  • Source: Wells PS et al. (2000)

About Wells' Criteria for PE

The Wells' Criteria for Pulmonary Embolism is a risk stratification score used to estimate the pre-test probability of acute pulmonary embolism in patients in whom PE is considered a diagnostic possibility.

Interpretation (Three-Tier Model)

  • Low Risk (Score < 2): 1.3% probability of PE. Consider D-dimer rule out.
  • Moderate Risk (Score 2-6): 16.2% probability of PE. Consider D-dimer or CTA depending on sensitivity.
  • High Risk (Score > 6): 40.6% probability of PE. CT Angiogram is recommended (skip D-dimer).

Interpretation (Two-Tier Model)

  • PE Unlikely (Score ≤ 4): 12.1% incidence. High-sensitivity D-dimer is recommended.
  • PE Likely (Score > 4): 37.1% incidence. CT Angiogram is recommended.

Primary Literature & Validation Citations

  1. Derivation Study: Wells PS, Anderson DR, Rodger M, et al. Derivation of a simple clinical model to categorize patients probability of pulmonary embolism: increasing the models utility with the SimpliRED D-dimer. Thromb Haemost. 2000;83(3):416-420.[PubMed PMID: 10744147]
  2. Prospective Bedside Validation: Wells PS, Anderson DR, Rodger M, 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. Ann Intern Med. 2001;135(2):98-107.[PubMed PMID: 11453709]

Disclaimer: This tool is intended for educational and reference purposes only. It should not be used as a substitute for professional medical judgment or advice.

Clinically reviewed by Jed Whetten, MD Candidate (Univ. of Arizona COM-Phoenix) • Verified September 2026