Wells Score for DVT
Calculates the probability of deep vein thrombosis (DVT) using the Wells criteria to guide diagnostic testing decisions.
Clinical Criteria
Patient receiving treatment or palliative care within 6 months
Recently bedridden >3 days or major surgery requiring general/regional anesthesia within 12 weeks
Measured 10 cm below tibial tuberosity
Collateral (non-varicose) superficial veins present
Entire leg is swollen
Localized tenderness along the distribution of the deep venous system
Pitting edema confined to the symptomatic leg
Paralysis, paresis, or recent plaster immobilization of lower extremity
History of objectively documented DVT
Alternative diagnosis to DVT is at least as likely (subtracts 2 points)
Scoring
Wells DVT Score
Enter values to calculate
About This Calculator
The Wells Score for DVT is an evidence-based clinical decision-making tool developed by Dr. Phil Wells and colleagues in 1997. It assesses the pre-test probability of deep vein thrombosis in patients presenting with symptoms suggestive of DVT.
The score uses clinical parameters to stratify patients into low, moderate, or high probability categories. This stratification helps clinicians determine the appropriate diagnostic pathway: • Low probability patients may be safely ruled out with a negative D-dimer • Moderate probability patients typically need D-dimer testing with possible imaging • High probability patients should proceed directly to imaging (compression ultrasound)
The Wells criteria are most validated in outpatient settings and emergency departments. They are less reliable in hospitalized or post-operative patients.
Key principle: High clinical suspicion should prompt imaging regardless of the Wells score.
Formula
Wells DVT Score = Sum of present criteria (each +1) - 2 if alternative diagnosis likelyEach positive criterion adds 1 point: • Active cancer (treatment within 6 months) • Bedridden >3 days or major surgery within 12 weeks • Calf swelling >3 cm compared to asymptomatic leg • Collateral superficial veins (non-varicose) • Entire leg swollen • Localized tenderness along deep venous system • Pitting edema confined to symptomatic leg • Paralysis, paresis, or recent plaster immobilization • Previously documented DVT Subtract 2 points if alternative diagnosis is at least as likely as DVT.
Clinical Considerations
- •The Wells score is most validated in outpatient and ED settings
- •Less reliable in hospitalized or post-operative patients
- •High clinical suspicion should prompt imaging regardless of score
- •Should be used in conjunction with clinical judgment
- •Age-adjusted D-dimer cutoffs may be considered in older patients
- •Pregnant patients may require modified diagnostic approaches
Limitations
- •Developed and validated primarily in outpatient populations
- •May underestimate risk in hospitalized patients
- •Does not apply to upper extremity DVT
- •Inter-observer variability in "alternative diagnosis" assessment
- •Does not account for all risk factors (e.g., thrombophilia)
Interpretation Guide
| Range | Classification | Recommendation |
|---|---|---|
| -2-1 | Low Probability | Low pre-test probability. Check D-dimer. If negative, DVT is effectively ruled out. If positive, proceed to compression ultrasound. |
| 1-3 | Moderate Probability | Moderate pre-test probability. Check D-dimer or proceed directly to compression ultrasound based on clinical context and local protocols. |
| 3-10 | High Probability | High pre-test probability. Proceed directly to compression ultrasound. Consider anticoagulation while awaiting imaging if high suspicion. |
Frequently Asked Questions
What is the Wells Score for DVT?
The Wells Score is a clinical prediction rule that estimates the pre-test probability of deep vein thrombosis. It uses clinical criteria to categorize patients into low, moderate, or high probability groups, guiding decisions about D-dimer testing and imaging.
Can a negative D-dimer rule out DVT?
In low probability patients (Wells score ≤0), a negative highly-sensitive D-dimer effectively rules out DVT without need for imaging. However, in high probability patients, imaging should be performed regardless of D-dimer results.
What imaging is used to diagnose DVT?
Compression ultrasonography is the primary imaging modality for diagnosing DVT. It is non-invasive, readily available, and has high sensitivity and specificity for proximal DVT. Whole-leg ultrasound can also detect isolated calf vein thrombosis.
Should I start anticoagulation before imaging?
In patients with high clinical suspicion and high Wells score, empiric anticoagulation may be considered while awaiting diagnostic imaging, particularly if there will be a delay in obtaining the ultrasound. Discuss with your clinical team.
Is the Wells score accurate in hospitalized patients?
The Wells score is less validated in hospitalized patients and may underestimate DVT risk in this population. Clinical judgment is particularly important in inpatients, and a lower threshold for imaging may be appropriate.
References
1. Wells PS, Anderson DR, Bormanis J, et al.. Value of assessment of pretest probability of deep-vein thrombosis in clinical management. The Lancet. 1997. doi: 10.1016/S0140-6736(97)08140-3
View Source →2. Wells PS, Anderson DR, Rodger M, et al.. Evaluation of D-dimer in the diagnosis of suspected deep-vein thrombosis. New England Journal of Medicine. 2003. doi: 10.1056/NEJMoa023153
View Source →3. Lim W, Le Gal G, Bates SM, et al.. American Society of Hematology 2018 guidelines for management of venous thromboembolism. Blood Advances. 2018. doi: 10.1182/bloodadvances.2018024828
View Source →Last updated: 2025-01-15
Auto-Calculate Wells DVT in Your Clinical Notes
PatientNotes AI automatically captures patient data during your visit and calculates relevant clinical values directly in your documentation. No manual entry needed—just review and approve.
7-day free trial • No credit card required • HIPAA compliant