Emergency and Critical Care

Wells Score for Pulmonary Embolism (PE)

Assesses clinical probability of pulmonary embolism

Primary source: Wells PS et al. Thromb Haemost 2000; 83(3): 416-420

Aleksandr A. Aulov, MD, internal medicine Last clinical review: April 28, 2026

Online calculation

Clinical signs of DVT (edema, tenderness on deep vein palpation)

PE more likely than an alternative diagnosis

Heart rate > 100/min

Immobilization ≥ 3 days or surgery in the past 4 weeks

Previous DVT or PE

Hemoptysis

Malignancy (treatment within the past 6 months or palliative care)

About this score

The Wells score for pulmonary embolism (P. S. Wells et al., Ann Intern Med, 2001) is a clinical pretest probability tool for PE. It is used before ordering D-dimer and/or CT pulmonary angiography to rationally triage patients with suspected embolism.

The score includes 7 weighted parameters: clinical signs of DVT (3 points), PE more likely than an alternative diagnosis (3 points), heart rate > 100 (1.5), immobilization or surgery in the past 4 weeks (1.5), previous DVT or PE (1.5), hemoptysis (1), active malignancy (1).

Two-tier interpretation: ≤ 4 — PE unlikely (can be excluded with a negative D-dimer), > 4 — PE likely (imaging required: CT pulmonary angiography or V/Q scan). Current ESC 2019 guidelines favor the two-tier version as simpler and sufficiently accurate.

When to use

Patient with acute-onset dyspnea, pleuritic chest pain, or hemoptysis of unclear etiology.
Postoperative patient with tachycardia, hypoxia, or unexplained syncope.
Deciding whether D-dimer testing is appropriate (if the score indicates low probability).
Deciding whether CT pulmonary angiography is needed — the primary confirmatory test when probability is high.

Clinical example

Case

55-year-old woman, postoperative day 5 after knee arthroplasty. Reports acute-onset dyspnea and stabbing right-sided chest pain on inspiration. Exam: heart rate 108/min, BP 130/80, SpO2 92% on room air, respiratory rate 22/min, right calf with edema and tenderness along the deep veins. No hemoptysis.

Calculation

Signs of DVT (3) + PE more likely than an alternative diagnosis (3) + heart rate > 100 (1.5) + immobilization/surgery (1.5) = 9 points.

Interpretation and management

High pretest probability of PE. D-dimer is not performed, as it would almost certainly be positive. Emergency CT pulmonary angiography is indicated. In parallel, assess severity with PESI/sPESI and obtain echocardiography. If PE is confirmed, initiate full-dose anticoagulation.

Limitations and cautions

Subjectivity of the item 'PE more likely than an alternative diagnosis' — the score's accuracy depends on the clinician's judgment.
Used with caveats in pregnancy, since D-dimer is physiologically elevated; adapted algorithms are used instead (YEARS, pregnancy-adapted Wells).
In older adults, standard D-dimer is often positive regardless of PE; an age-adjusted threshold is used (age × 10 ng/mL).
Does not assess the severity of confirmed PE — PESI or sPESI are used for that.

Frequently asked questions

Which version should be used — the two-tier or three-tier score?

Current guidelines favor the two-tier version as more practical: ≤ 4 — rule out with D-dimer, > 4 — proceed directly to imaging.

If the Wells score is low, can D-dimer testing be skipped?

No. PE is ruled out only by the combination of low clinical probability and a negative D-dimer. Without D-dimer testing, formal exclusion is not possible.

Wells vs Geneva score — which should be used?

Accuracy is comparable. The Geneva score is more objective, since it lacks the subjective 'PE more likely' item, while Wells is simpler and faster. Choose based on institutional protocol.

Can it be used in a patient with CKD?

The score itself, yes. The problem arises at the CT pulmonary angiography step, due to contrast-induced nephropathy. At eGFR < 30, consider V/Q scintigraphy or MR angiography.

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Aleksandr A. Aulov Physician, internal medicine, Sechenov School — independent medical education platform. Calculators are compiled from the original publications and current clinical guidelines. Interpretation thresholds follow the source study unless stated otherwise.

This calculator is intended for healthcare professionals. Do not use it for self-diagnosis or self-treatment. Management decisions are made by the treating clinician based on the full clinical picture of the individual patient.