Wells Score (PE)

What This Calculator Measures

Estimates the pre-test probability of pulmonary embolism to guide D-dimer testing and imaging decisions.

How to Use

1. Assess each of the seven clinical items in the Wells criteria.
2. Select Yes for each criterion that is present.
3. The weighted score is totaled automatically.
4. Use the two-tier interpretation for D-dimer-driven strategies.

Interpretation Guide

Two-tier: score ≤4 = PE unlikely (negative high-sensitivity D-dimer safely excludes PE); score >4 = PE likely (proceed to CT pulmonary angiography). Three-tier: 0–1 low, 2–6 moderate, >6 high probability.

Clinical Significance

The Wells criteria enable risk-stratified testing for PE, reducing unnecessary CT angiography while maintaining diagnostic safety when paired with a high-sensitivity D-dimer.

When to Use

• Emergency department evaluation of suspected PE
• Deciding whether a D-dimer test is appropriate
• Structuring the clinical assessment of dyspnea or pleuritic chest pain

When Not to Use

• Hemodynamically unstable patients who need immediate imaging or treatment
• Patients with an alternative confirmed diagnosis
• As a stand-alone test; it is a pre-test probability tool, not a diagnostic test

Limitations

• Several items ('PE most likely diagnosis') are subjective and operator-dependent.
• Pre-test probability tools perform differently in inpatient versus outpatient populations.
• The score does not replace diagnostic testing in intermediate or high probability patients.
• A low score does not by itself exclude PE — persistent clinical suspicion warrants continued evaluation.

Worked Example

A 40-year-old woman presents with palpitations and mild dyspnea, HR 118 bpm. She has no DVT signs, no immobilization, no prior VTE, and no malignancy; PE is not felt to be the most likely diagnosis.

Wells score 1.5 — PE unlikely. A negative high-sensitivity D-dimer safely excludes PE without imaging.

Evidence

Source

Wells PE Criteria

Reference

Wells PS, 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.

Reviewed By

MedCalcHub Clinical Team

Version

1.0

Updated

2026-08

1. Wells PS, et al. Ann Intern Med. 2001;135(2):98-107.
2. Wells PS, et al. Thromb Haemost. 2000;83(3):416-420.

References

1. Wells PS, 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. (Management Study)
2. Wells PS, 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. (Original Derivation)

Frequently Asked Questions