Pre-test probability of pulmonary embolism. Free to use.
Wells Score (PE) (Wells Criteria for Pulmonary Embolism) is a validated clinical instrument used to assess pre-test probability of pulmonary embolism. The instrument contains 7 items.
Source / attribution: Wells PS et al., Thromb Haemost 2000
The instrument's primary construct — pre-test probability of pulmonary embolism — is operationalized through a fixed set of items, each with a defined response format. This standardisation is what allows Wells Score (PE) scores to be compared meaningfully across clinicians, sites, and studies.
Like all screening or assessment instruments, Wells Score (PE) is a structured aid — not a diagnostic test in isolation. Results should be interpreted alongside history, examination, and clinical context. Where a score crosses an actionable threshold, the next step is typically a more detailed clinical evaluation rather than a definitive diagnosis.
Answer all 7 items below to see your Wells Score (PE) score and interpretation.
All scoring runs in your browser. No data is sent anywhere — close the tab and the answers are gone.
Wells Score (PE) uses weighted summation: each item carries a fixed weight that is added when the response indicates a positive finding.
Scoring notes: Educational use only. Not a substitute for clinical judgment.
The cutoffs below are drawn from the published validation literature. Always interpret in clinical context.
| Score range | Band | Interpretation |
|---|---|---|
| 0–1.5 | Low probability | PE unlikely. |
| 2–6 | Moderate probability | PE possible — needs further testing. |
| 6.5–12.5 | High probability | PE likely — image now. |
This is an illustrative walkthrough, not a real patient. Follow the same four steps with your own answers — or use the live calculator at the top of this page.
Mark each item Yes or No. Each "Yes" adds the item's weight; each "No" adds 0. The example below uses illustrative answers.
| # | Item | Example response | Score |
|---|---|---|---|
| 1 | Clinical signs/symptoms of DVT | No | 0 |
| 2 | PE is #1 diagnosis or equally likely | No | 0 |
| 3 | Heart rate > 100 bpm | Yes | 1.5 |
| 4 | Immobilization ≥ 3 days OR surgery in past 4 weeks | No | 0 |
| 5 | Previous DVT or PE | Yes | 1.5 |
| 6 | Hemoptysis | Yes | 1 |
| 7 | Malignancy (treatment within 6 months or palliative) | No | 0 |
Add the weights from the items where you marked "Yes" (skip the "No" answers — they contribute 0).
0 + 0 + 1.5 + 0 + 1.5 + 1 + 0 = 4
Find the row in the interpretation table whose range contains your total:
Total = 4 falls between 2 and 6 → Moderate probability
Moderate probability. D-dimer; image if positive.
A score is one input alongside history and examination. Wells Score (PE) supports clinical judgment — it does not replace it.
If Wells Score (PE) doesn't fit your context, related instruments in pulmonology include:
| Scale | Measures | Items | Time |
|---|---|---|---|
| CURB-65 | 30-day mortality in community-acquired pneumonia | 5 | — |
| mMRC Dyspnea Scale | Functional impact of breathlessness | 1 | — |
| PERC Rule | Rule out PE in low-risk patients | 8 | — |
| sPESI | 30-day mortality risk after acute PE | 6 | — |
| APGAR Score | Rapid assessment of newborn at 1 and 5 min | 5 | — |
| ASA Physical Status | Pre-operative health status | 1 | — |
| CHA2DS2-VASc | Annual stroke risk in non-valvular atrial fibrillation | 8 | — |
| Glasgow Coma Scale | Level of consciousness after head injury | 3 | — |
Wells Score (PE) (Wells Criteria for Pulmonary Embolism) is a validated instrument that assesses pre-test probability of pulmonary embolism. It is designed for clinicians, medical students, evidence-synthesis researchers. The 7 items are combined to produce a total score.
Wells Score (PE) contains 7 items. Item scores are combined with weighted scoring to produce the total. Scores run from 0 to 12.5, grouped into 3 interpretation bands from ‘Low probability’ up to ‘High probability’.
On the Wells Score (PE) (total score 0–12.5), scores of 6.5–12.5 fall in the ‘High probability’ band — interpreted as: PE likely — image now. The full ladder is: 0–1.5 — Low probability: PE unlikely.; 2–6 — Moderate probability: PE possible — needs further testing.; 6.5–12.5 — High probability: PE likely — image now. A higher score reflects a more severe presentation, and crossing a cutoff is a prompt to step up assessment or care — but these bands are screening thresholds, not diagnoses.
Scores of 0–1.5 fall in the ‘Low probability’ band: PE unlikely. A low score is reassuring but does not by itself rule out the underlying condition — if symptoms or clinical suspicion persist, reassess over time or use a complementary evaluation rather than relying on the number alone.
Yes — Wells Score (PE) is in the public domain and free for clinical, educational, and research use without permission. You can use this calculator and the scale itself freely; if you publish results or reproduce the scale, cite the original source paper.
Wells PS et al. Thromb Haemost. 2000;83(3):416-420. This is the original publication for the Wells Score (PE) — the reference to cite when reporting results.
No. Wells Score (PE) is a structured assessment aid, not a diagnostic test. Its proper role is clinical assessment of pre-test probability of pulmonary embolism — it standardizes assessment and flags who needs closer evaluation, but the result must be weighed alongside history, examination, and clinical context. When a score conflicts with your clinical impression, clinical judgment takes precedence; treatment decisions should never rest on a screening score alone.
Wells Score (PE) is supported by the following peer-reviewed sources: