The Wells score is a number that reflects your risk of developing deep vein thrombosis (DVT). DVT happens when a blood clot forms in a vein that’s deep inside your body, usually in your leg. Your Wells score is calculated based on several factors. Using this score, your doctor can determine your likelihood of having DVT. This helps your doctor decide whether to proceed with further diagnostic testing, such as a CT scan.

Your doctor will check for several symptoms and risk factors. Each of these is assigned a point value. After evaluating you, your doctor will add up the points to get your Wells score.

Some doctors prefer to use their own modified version of a Wells score, so your doctor may use slightly different criteria.

Symptom and risk factorsPoints
Active cancer, or cancer that’s been treated within last six months1
Paralyzed leg1
Recently bedridden for more than three days or had major surgery within last four weeks1
Tenderness near a deep vein1
Swollen leg1
Swollen calf with diameter that’s more than 3 centimeters larger than the other calf’s 1
Pitting edema in one leg1
Large veins in your legs that aren’t varicose veins1
Previously diagnosed with DVT1
Other diagnosis more likely-2

Your doctor will interpret your Wells score based on either a two-tier or three-tier model. If your score indicates you have a higher risk of DVT, your doctor might do additional testing, such as a venogram.

Two-tier model

ScoreResult
2 or higherDVT is likely
1 or lowerDVT is not likely

Three-tier model

ScoreResult
3 or higherHigh risk of DVT
1 or 2Moderate risk of DVT
0 or lessLow risk of DVT

Your Wells score can help your doctor determine your risk of developing DVT. If your score indicates you have a higher risk, your doctor may suggest additional testing to look for a blood clot. If your risk is low, they may simply monitor you for any new symptoms.