Wells Score Calculator for PE
Estimate the pre-test probability of pulmonary embolism (PE) using the Wells clinical prediction score. Each finding adds its own weight — clinical DVT and “PE is the most likely diagnosis” count most. The score sorts patients into likelihoods that guide whether to use D-dimer or move to CT pulmonary angiography. Tick the findings that are present.
The Wells PE criteria
Seven weighted findings, maximum 12.5. See also the Wells score for DVT. Source: Wells PS et al., Ann Intern Med 2001 and Thromb Haemost 2000; two-tier model per ACEP guidance.
Frequently asked questions
How is the Wells PE score calculated?
Points are: clinical signs and symptoms of DVT (3), PE is the most likely diagnosis or equally likely (3), heart rate over 100 (1.5), immobilization at least 3 days or surgery in the previous 4 weeks (1.5), a previous PE or DVT (1.5), haemoptysis (1), and malignancy treated within 6 months or palliative (1). The total therefore runs from 0 to a maximum of 12.5. The two three-point items — clinical signs of DVT, and PE being the most likely diagnosis — carry the most weight: together they give 6, above the two-tier “PE likely” threshold of 4 and at the top of the moderate band on the three-tier scale. Tick the criteria that are present and the calculator handles the half-point weights, which is where hand calculation most often slips.
What do the Wells PE categories mean?
In the three-tier Wells score for PE, under 2 is low probability, 2–6 is moderate and over 6 is high. In the two-tier version, which many guidelines now prefer, a score of 4 or less is “PE unlikely” and over 4 is “PE likely.” The two-tier split pairs with D-dimer testing to safely rule PE out in the unlikely group. Which version you use matters at the margins: a score of 3 is moderate probability on the three-tier scale but still “PE unlikely” on the two-tier one. Local pathways specify which split applies, so follow the version your D-dimer protocol was built around.
What happens after the score?
A common pathway after the Wells PE score is: PE unlikely (≤ 4) → D-dimer; a negative (often age-adjusted) D-dimer rules PE out, while a positive one prompts CT pulmonary angiography. PE likely (> 4) → proceed to CT pulmonary angiography (or a V/Q scan). The PERC rule can also help avoid testing in very low-risk patients. Protocols vary and remain a clinical decision.
What counts as “PE is the most likely diagnosis”?
The “PE is the most likely diagnosis” item is a clinical judgement that no alternative explanation (such as pneumonia, heart failure or musculoskeletal pain) is more likely than PE for the presentation. Because it is subjective and carries three points, it strongly influences the result and should reflect a careful assessment of the whole picture. In practice it asks whether, after considering the alternatives, PE still sits at the top of your differential — an equal ranking counts, since the criterion is worded as most likely or equally likely. Being the most subjective item on the list, it is also the one on which two clinicians most often score the same patient differently.
When should the Wells PE score not be relied on?
The Wells PE score estimates pre-test probability for suspected PE and is designed to be used with D-dimer and imaging, not alone. It was not derived for pregnancy or for confirming PE, and clinical gestalt still matters. This calculator is an educational reference, not medical advice.
This is a reference tool, not a diagnosis or medical advice. Results depend on the laboratory, assay and clinical context, and reference intervals vary between labs and by age and sex — always read your result against the range printed on your own report and discuss it with a qualified healthcare professional.
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