Wells PE score: how the points are calculated

The Wells score for pulmonary embolism (PE) adds weighted points for seven items: clinical signs of deep vein thrombosis (3 points), PE being the leading possibility or equally likely (3), heart rate over 100 (1.5), immobilization or recent surgery (1.5), a previous DVT or PE (1.5), coughing up blood (1), and cancer (1). The total runs from 0 to 12.5 in half-point steps. Signs of DVT plus PE as the leading possibility, with nothing else, scores 6.

Not a medical device. Not a diagnosis or dosing recommendation.

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Infection and VTE calculators
Wells PS et al. · 2001
The Wells PE formula
Worked examples
Wells PE points table
Frequently asked questions

What is the Wells PE score?

The Wells PE score is a clinical model for suspected pulmonary embolism, from Philip S. Wells and colleagues. Magent's calculator cites their 2001 paper in Annals of Internal Medicine, which used the model in emergency departments.

It's also called the Wells criteria for PE or the Wells pulmonary embolism score.

This page explains the arithmetic. It doesn't give a cutoff, it doesn't sort totals into probability groups, and it doesn't say what a score means for a particular person.

The Wells PE formula

Wells PE = 3 × signs of DVT
         + 3 × PE is the leading possibility (or equally likely)
         + 1.5 × heart rate > 100
         + 1.5 × immobilization or recent surgery
         + 1.5 × previous DVT or PE
         + 1 × hemoptysis
         + 1 × malignancy
range = 0 to 12.5

Exact expression the calculator uses:

Wells PE = 3*signs_dvt + 3*pe_number_one + 1.5*hr_gt_100 + 1.5*immobilization_or_surgery + 1.5*previous_dvt_pe + 1*hemoptysis + 1*malignancy

What each part means

Input	Item	Points
`signs_dvt`	Clinical signs and symptoms of DVT	3
`pe_number_one`	PE is the number-one possibility, or equally likely	3
`hr_gt_100`	Heart rate over 100 beats per minute	1.5
`immobilization_or_surgery`	Immobilized 3 days or more, or surgery in the previous 4 weeks	1.5
`previous_dvt_pe`	A previous DVT or PE	1.5
`hemoptysis`	Coughing up blood	1
`malignancy`	Cancer that has been treated in the last 6 months, or is in palliative care	1

How the score works

Go through the seven items. Each is yes or no.
Use each item's weight. Two items are worth 3, three are worth 1.5, and two are worth 1.
Add them up. The total is 0 to 12.5. Because three items are worth 1.5, the total can end in a half.

Half points

The 1.5-point items are why Wells PE totals can include halves. Magent's calculator returns the total as a decimal, the maximum of 12.5, and a line for each item. It also returns group labels for the total; this page doesn't describe them.

Worked examples

These use Magent's own expected values for the calculator, plus one example (example 3) worked from the formula.

Example 1: no items

None of the seven items.
Score = 0.

Example 2: signs of DVT and PE as the leading possibility

Signs of DVT → 3.
PE is the number-one possibility → 3.
Score = 6.

Example 3: heart rate over 100 alone

Heart rate over 100 → 1.5.
Score = 1.5.

Example 4: every item

Signs of DVT → 3; PE as leading possibility → 3.
Heart rate over 100 → 1.5; immobilization or surgery → 1.5; previous DVT or PE → 1.5.
Hemoptysis → 1; malignancy → 1.
Score = 3 + 3 + 1.5 + 1.5 + 1.5 + 1 + 1 = 12.5, the maximum.

Wells PE points table

Item	Points if present
Clinical signs of DVT	3
PE is the number-one possibility or equally likely	3
Heart rate over 100	1.5
Immobilization 3+ days or surgery in previous 4 weeks	1.5
Previous DVT or PE	1.5
Hemoptysis	1
Malignancy	1
Highest possible total	12.5

History of the Wells PE score

The calculator cites Philip S. Wells, David R. Anderson, Marc Rodger and colleagues, Excluding pulmonary embolism at the bedside without diagnostic imaging: management of patients with suspected pulmonary embolism presenting to the emergency department by using a simple clinical model and d-dimer, Annals of Internal Medicine 2001 (volume 135, issue 2, pages 98–107).

The abstract describes a prospective cohort study of 930 consecutive patients with suspected PE in the emergency departments of four tertiary care hospitals in Canada. Physicians first used a clinical model to estimate each patient's pretest probability of PE. The abstract also says the authors had shown earlier that working out the pretest probability can help.

When it's used

The 2001 abstract describes physicians using the clinical model first, for patients who came to the emergency department with suspected PE.

Where it's used

The 2001 study took place in the emergency departments of four tertiary care hospitals in Canada.

Who uses it

In the 2001 study, physicians applied the model. With Magent's calculator, the person using it answers each yes/no item. The record says the calculator doesn't read imaging or blood tests.

Limits of the calculation

It adds up seven weighted items. It doesn't diagnose or rule out a PE.
The "PE is the number-one possibility" item is a judgment made by the person using the calculator.
Items come from the user. Nothing is inferred from notes, imaging or blood tests.
This page doesn't say what to do with a score.

Clinical decisions belong to a qualified clinician who knows the patient.

Wells DVT is a separate score for suspected deep vein thrombosis. It gives 1 point to each of nine findings and subtracts 2 when another explanation is at least as likely.

Glossary

Pulmonary embolism (PE): a blood clot that has traveled to the arteries of the lungs.
Deep vein thrombosis (DVT): a blood clot in a deep vein, usually in the leg.
Hemoptysis: coughing up blood.
Malignancy: cancer.
Pretest probability: an estimate of how likely a condition is before tests are done.

Common mistakes

Giving every item 1 point. The weights are 3, 1.5 and 1.
Rounding 1.5-point items. Totals can end in a half; keep the half.
Using the DVT items. Wells PE has its own seven items.
Counting surgery from 2 months ago. The surgery item covers the previous 4 weeks.

Source

Wells PS, Anderson DR, Rodger M, et al. Excluding pulmonary embolism at the bedside without diagnostic imaging: management of patients with suspected pulmonary embolism presenting to the emergency department by using a simple clinical model and d-dimer. Ann Intern Med. 2001;135(2):98-107. DOI: 10.7326/0003-4819-135-2-200107170-00010

Frequently asked questions

How do you calculate the Wells PE score?

Add 3 for signs of DVT, 3 if PE is the leading possibility, 1.5 each for heart rate over 100, immobilization or recent surgery, and a previous DVT or PE, and 1 each for hemoptysis and cancer. The total is 0 to 12.5.

What Wells score means PE is likely?

This page doesn't give a cutoff or sort scores into groups. It adds up the points; what a score means depends on the person and the clinical context.

Why does the Wells PE score have half points?

Three items are worth 1.5 points each, so totals can end in a half.

Does a heart rate of exactly 100 count?

No. The item is for a heart rate over 100 beats per minute. The calculator takes it as a yes/no answer, so the person using it decides whether the rate is over 100.

Does any past surgery count?

No. The item covers surgery in the previous 4 weeks, or immobilization for 3 days or more. Either one earns the same 1.5 points; they don't add together.

What is the highest Wells PE score?

12.5, with all seven items present.

Is the Wells PE score the same as the Wells DVT score?

No. They're separate scores with different items and weights.

Who developed the Wells PE score?

Philip S. Wells and colleagues. Magent's calculator cites their 2001 Annals of Internal Medicine paper.