How do the PE and DVT versions differ?

They are different sign sets and thresholds: the PE version estimates a clot in the lungs, the DVT version in the leg veins. DVT has a “−2 points” item if an alternative diagnosis is at least as likely.

What to do at low probability?

A D-dimer is usually ordered: if negative at low probability, thrombosis can be excluded without CT/ultrasound. At moderate and high probability, imaging is done straight away.

Does the Wells score make a diagnosis?

No. It is a pre-test clinical probability. Diagnosis is by D-dimer, CT angiography (PE) or venous ultrasound (DVT) — decided by a doctor.

When is emergency care needed?

With PE symptoms — sudden shortness of breath, chest pain, rapid heartbeat, fainting — call emergency services immediately, without waiting to add up points.

Wells score: probability of PE and DVT

Q: How do I use the Wells score?

Choose the version (PE or DVT) and check the clinical signs present. The calculator sums the points and shows the probability (low/moderate/high) and a two-tier “likely/unlikely” read.

The Wells score helps estimate the clinical probability of thrombosis — before labs and imaging. Choose the version (PE or DVT) and check the signs present — the calculator sums the points and shows the probability: low, moderate or high, plus a two-tier “likely / unlikely” read. It is a tool for clinicians, not self-diagnosis.

Estimate probability with the Wells score

Wells score

0points

Low probability

Two-tier read: unlikely

A pre-test clinical probability of thrombosis. Next comes a D-dimer, CT or venous ultrasound as the doctor decides. This is not a diagnosis.

A probability estimate, not a diagnosis. With PE symptoms (shortness of breath, chest pain, fainting) call emergency services immediately.

Wells score probability levels

Point thresholds differ for PE and DVT. The result is a probability estimate, not a diagnosis; the next step (D-dimer, CT, venous ultrasound) is decided by a doctor.

Version	Points → probability
PE	< 2 low · 2–6 moderate · > 6 high
DVT	< 1 low · 1–2 moderate · ≥ 3 high

What the Wells score is

The Wells score is a set of clinical signs used to estimate the probability of venous thromboembolism before instrumental testing. Each sign has a point value; the sum sets the probability.

It is not a diagnosis but a way to decide what to do next: who needs only a D-dimer test, and who needs imaging straight away (CT angiography for PE, venous ultrasound for DVT).

Two versions — PE and DVT

The PE (pulmonary embolism) version estimates the risk of a clot in the lungs; the DVT (deep vein thrombosis) version — a clot in the leg veins. Their sign sets and thresholds differ, so pick the right tab.

The DVT version has a negative item: if an alternative diagnosis is at least as likely, 2 points are subtracted.

What to do with the result

At low probability (or “unlikely”), a D-dimer is usually ordered: a negative result rules out thrombosis without imaging. At moderate/high probability, imaging follows.

The pathway depends on the clinic and local protocols — a doctor decides. If PE is suspected (shortness of breath, chest pain, fainting), care is needed urgently.

An estimate, not a diagnosis

The calculator structures the assessment but does not replace a doctor. Signs must be determined clinically; the result is interpreted together with labs and imaging.

Frequently asked questions

Choose the version (PE or DVT) and check the clinical signs present. The calculator sums the points and shows the probability (low/moderate/high) and a two-tier “likely/unlikely” read.
They are different sign sets and thresholds: the PE version estimates a clot in the lungs, the DVT version in the leg veins. DVT has a “−2 points” item if an alternative diagnosis is at least as likely.
A D-dimer is usually ordered: if negative at low probability, thrombosis can be excluded without CT/ultrasound. At moderate and high probability, imaging is done straight away.
No. It is a pre-test clinical probability. Diagnosis is by D-dimer, CT angiography (PE) or venous ultrasound (DVT) — decided by a doctor.
With PE symptoms — sudden shortness of breath, chest pain, rapid heartbeat, fainting — call emergency services immediately, without waiting to add up points.

A CT or venous ultrasound — we’ll explain the scan

Upload the scan or report — AI explains the findings in plain language and suggests what to ask your doctor.

Decode a scan

This calculator is for reference and information only and is not a diagnosis. Thrombosis is diagnosed by a doctor; with PE symptoms call emergency services immediately.