Printed on 3/17/2026
For informational purposes only. This is not medical advice.
The Wells Score for PE is a clinical prediction tool that estimates the pre-test probability of pulmonary embolism. It uses clinical signs, symptoms, and risk factors to stratify patients into low, moderate, or high probability categories, guiding the clinician's decision on whether to order D-dimer testing or proceed directly to CT pulmonary angiography (CTPA).
Formula: Wells PE = DVT symptoms(3) + PE likely(3) + HR>100(1.5) + Immobilization(1.5) + Previous(1.5) + Hemoptysis(1) + Cancer(1)
Evaluate for DVT signs (leg swelling, calf tenderness), check heart rate, review recent immobilization or surgery, and consider whether PE is the most likely diagnosis.
Award points for each positive finding. Clinical signs of DVT and 'PE most likely' are worth 3 points each; other criteria range from 1-1.5 points.
Low probability: check D-dimer. Moderate: D-dimer with CTPA if positive. High probability (>6): proceed directly to CTPA imaging.
Emergency physicians
Stratify patients presenting with shortness of breath, chest pain, or hypoxia to determine whether PE workup is indicated and how to proceed. Assess oxygenation deficits with [A-a Gradient](/tools/aa-gradient) if hypoxic.
Surgeons, hospitalists
Evaluate post-surgical patients with new dyspnea or tachycardia. Recent surgery adds 1.5 points, increasing pre-test probability. For ICU patients with suspected PE, also calculate [APACHE II](/tools/apache-ii-score) or [SOFA Score](/tools/sofa-score) for severity assessment.
Oncologists, palliative care
Assess cancer patients with pulmonary symptoms. Cancer increases VTE risk; active malignancy adds 1 point to Wells PE.
Quality teams, EHR analysts
Build Wells PE into electronic decision support to ensure consistent, evidence-based PE evaluation across providers.
Radiologists, ED directors
Use D-dimer to avoid unnecessary CTPAs in low-probability patients, reducing radiation exposure and contrast administration.
Medical education
Train residents and students in structured PE evaluation. Wells provides a framework for systematic pre-test probability assessment.
This 3-point criterion asks whether, considering all alternatives, PE is your leading diagnosis. It incorporates clinical gestalt. If you think pneumonia (assess with [CURB-65](/tools/curb-65)) or pleuritis is more likely, don't check this box.
If PE suspicion is low (not 'PE most likely'), apply PERC criteria first. All 8 negative = no further testing needed. PERC can save you from ordering even a D-dimer.
Score 3 points only if the patient has both leg symptoms AND objective swelling/tenderness. Just leg pain without signs doesn't count. Examine the legs on every PE evaluation.
Wells >6 has ~67% PE prevalence. D-dimer can't rule out PE at this prevalence — the false-negative rate is unacceptable. Go directly to CTPA.
For patients >50 years, use age × 10 µg/L as the D-dimer threshold. This increases specificity in older patients while maintaining sensitivity.
Use the heart rate from triage or initial assessment. If it was >100 then but is now 95 after anxiolysis, the point still counts. Document the initial HR.
For patients with contrast allergy, severe renal disease (check [eGFR Calculator](/tools/egfr-calculator) or [Creatinine Clearance](/tools/creatinine-clearance)), or pregnancy, V/Q scanning is an alternative. Low-probability V/Q + low clinical probability rules out PE.
PE-associated hemoptysis is typically blood-streaked sputum from pulmonary infarction. Massive hemoptysis suggests other diagnoses. Any hemoptysis scores 1 point.
D-dimer is elevated in pregnancy. Many experts recommend compression ultrasound first (looking for DVT); if positive, treat without CTPA. If negative, V/Q or CTPA depending on gestational age (calculate with [Pregnancy Due Date Calculator](/tools/pregnancy-due-date)).
Write 'Wells PE = 4.5, proceeding with D-dimer' in your note. This documents your systematic approach and helps colleagues understand your decision-making.
Wells PE Score was developed by Wells et al. (Thromb Haemost 2000) and has been extensively validated. PERC was developed by Kline et al. (J Thromb Haemost 2004) to identify patients who don't need D-dimer. Age-adjusted D-dimer thresholds are supported by ADJUST-PE (JAMA 2014) and subsequent meta-analyses.
Your Wells PE score estimates the pre-test probability of pulmonary embolism. Using the three-tier model, a score below 2 indicates low probability (approximately 3.6% PE prevalence), 2–6 points indicates moderate probability (approximately 20.5%), and above 6 points indicates high probability (approximately 66.7%). Using the simplified two-tier model, a score of 4 or below is PE unlikely, and above 4 is PE likely.
As with the DVT score, this result guides the diagnostic workup rather than providing a definitive diagnosis. Low-probability patients can be evaluated with D-dimer first — a negative D-dimer in this group effectively rules out PE. Moderate-probability patients should have D-dimer testing, with CT pulmonary angiography (CTPA) if the D-dimer is positive. High-probability patients should proceed directly to CTPA without waiting for D-dimer results.
Use this calculator when evaluating a patient with symptoms that could represent pulmonary embolism — including acute dyspnea, pleuritic chest pain, tachycardia, hemoptysis, or unexplained hypoxia. It is a cornerstone of the PE diagnostic algorithm recommended by major guidelines (ACEP, BTS, ESC) and helps clinicians decide whether D-dimer testing alone is sufficient or whether imaging is needed.
The score is most impactful in the emergency department, where PE is a common diagnostic consideration for chest pain and dyspnea. By identifying patients with low pre-test probability who can be safely cleared with a negative D-dimer, it reduces unnecessary CTPA imaging — avoiding radiation exposure, contrast dye risks, and incidental findings that may lead to further testing.
The Wells PE score includes a highly subjective criterion: whether PE is the most likely diagnosis (worth 3 points). This element accounts for the clinician's gestalt and can swing the total score significantly, introducing inter-rater variability. Some studies have shown that experienced clinicians sometimes outperform the formal score using gestalt alone, while less experienced clinicians benefit more from structured scoring.
The score was validated in outpatient and emergency department populations and may not perform optimally in hospitalized or post-operative patients where the baseline prevalence of PE is different. It does not account for certain PE-specific risk factors such as recent long-haul air travel, thrombophilia, or nephrotic syndrome as independent criteria. In pregnant patients, the score has limited validation and clinical algorithms typically differ. Additionally, the PERC (Pulmonary Embolism Rule-out Criteria) rule may be more appropriate than Wells for very low-risk patients to avoid unnecessary D-dimer testing altogether.
For related assessments, see Wells Score (DVT), PERC Rule and A-a Gradient.
Disclaimer: This tool is for educational and informational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider with questions about your health.
Calculate the Wells Score to assess the clinical probability of deep vein thrombosis (DVT). Guide diagnostic workup and D-dimer testing.
EmergencyApply the PERC Rule to rule out pulmonary embolism in low-risk patients without D-dimer testing. Reduces unnecessary testing.
ClinicalCalculate the alveolar-arterial oxygen gradient to evaluate the cause of hypoxemia. Differentiates lung pathology from hypoventilation.