For healthcare professionals
Wells score for PE calculator
The Wells rule for pulmonary embolism (PE) is a clinical decision rule clinicians use to set the pretest probability of PE before D-dimer testing or imaging. Seven criteria score between 1 and 3 points. The total can be read in two ways: PE likely or unlikely, or low, intermediate or high probability. This calculator is written for clinicians and is not a diagnosis.
Clinical criteria
Tick each criterion that is present after history and examination. Nothing you enter leaves this page.
What you will see
The Wells PE score from 0 to 12.5, the points for each criterion, the two-level group (PE likely or unlikely) and the three-level group (low, intermediate or high).
Educational only, not medical advice. Not a diagnosis. PE is confirmed or excluded by testing, not by this score.
Source
Lucassen WAM et al., BMC Family Practice 2010 (open access, CC BY): Table 1, which prints the Wells clinical decision rule with its points and both sets of cut points, citing the original Wells studies. The tests check every item's points and each cut point.
Validated in
The paper describes management studies in secondary care (emergency department and hospital patients with suspected PE) in which the rule, combined with a normal D-dimer test, safely excluded PE in patients with a low or unlikely score, among them the Dutch Christopher study of 3,306 consecutive in- and outpatients (Lucassen 2010).
Limits
The score gives a pretest probability, not a diagnosis. It was developed and tested in secondary care; the paper notes that its use with point-of-care D-dimer tests in primary care had not been tested in a management study. The criterion 'alternative diagnosis less likely than PE' depends on clinical judgement. Pregnancy is not covered by this source.
Wells PE scoring
Add the points for each criterion present. A total of 4 or less means PE is unlikely and more than 4 means PE is likely. In the three-level version, under 2 points is low, 2 to 6 is intermediate and more than 6 is high clinical probability (Lucassen 2010).
| Criterion | Points |
|---|---|
| Clinical signs and symptoms of DVT (minimum of leg swelling and pain with palpation of the deep veins) | 3.0 |
| Alternative diagnosis less likely than PE | 3.0 |
| Heart rate over 100 per minute | 1.5 |
| Immobilization (more than 3 days) or surgery in the previous 4 weeks | 1.5 |
| Previous PE or DVT | 1.5 |
| Hemoptysis | 1.0 |
| Malignancy (receiving treatment, treated in the last 6 months, or palliative) | 1.0 |
| Reading | Points |
|---|---|
| Two-level: PE unlikely | 4 or less |
| Two-level: PE likely | more than 4 |
| Three-level: low | under 2 |
| Three-level: intermediate | 2 to 6 |
| Three-level: high | more than 6 |
Source: Table 1 of Lucassen et al., 2010, an open-access paper that reprints the Wells clinical decision rule (Lucassen 2010).
Testing after the score
The paper summarizes management studies in which PE was excluded safely in patients with a low (under 2) or unlikely (4 or less) score combined with a normal D-dimer test (Lucassen 2010). In the Christopher study it analyses, patients with PE unlikely had a quantitative D-dimer test, a normal result meant PE was considered excluded, and all other patients had CT (Lucassen 2010). Local pathways and the D-dimer assay in use may differ.
Related tools
For patients whose gestalt probability of PE is already low, the PERC rule calculator checks the 8 rule-out criteria. Once pulmonary embolism is confirmed, the PESI score calculator gives the 30-day mortality class (PESI and simplified PESI). For a swollen or painful leg, see the Wells score for DVT. For the risk of a future clot in a patient admitted to a medical ward, see the Padua prediction score. For other clinician scores on this site, see the HEART score calculator for chest pain and the CURB-65 calculator for pneumonia. For bleeding risk in people with atrial fibrillation who take a blood thinner, see the HAS-BLED score.
Sources
- Lucassen WAM, Douma RA, Toll DB, Buller HR, van Weert HCPM. Excluding pulmonary embolism in primary care using the Wells-rule in combination with a point-of care D-dimer test: a scenario analysis. BMC Fam Pract. 2010;11:64. doi:10.1186/1471-2296-11-64. Open access (CC BY 2.0). Table 1 (Wells clinical decision rule), Background and Methods. pmc.ncbi.nlm.nih.gov/articles/PMC2944151/
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