This calculator uses the adult Wells DVT pretest score. Each positive clinical criterion adds 1 point, while “alternative diagnosis at least as likely as DVT” subtracts 2 points.
Formula:
Two-level interpretation:
- Score < 2: DVT Unlikely
- Score ≥ 2: DVT Likely
Three-level band shown for quick review:
- Score ≤ 0: Low
- Score 1 to 2: Moderate
- Score ≥ 3: High
- Enter optional patient details if you want them included in exports.
- Select the symptomatic leg and add calf circumferences when measured.
- Turn on every Wells criterion that is clinically present.
- Click the calculate button to generate total score, category, breakdown, and graph.
- Review the suggested next-step text, then confirm decisions with local protocol and clinician judgment.
| Case | Key Findings | Score | Two-Level Category | Comment |
|---|---|---|---|---|
| Example A | Localized tenderness, entire leg swelling, calf difference 4.1 cm, previous DVT | 4 | DVT Likely | Strong clinical suspicion and urgent imaging pathway. |
| Example B | Recent major surgery, pitting edema in symptomatic leg | 2 | DVT Likely | Crosses likely threshold despite fewer findings. |
| Example C | Mild leg symptoms with plausible cellulitis as alternative diagnosis | -2 | DVT Unlikely | Lower pretest probability, but still needs clinical context. |
1. What does this calculator estimate?
It estimates pretest probability using the Wells DVT rule. It supports triage and imaging decisions, but it does not diagnose, rule out, or treat DVT by itself.
2. Does age change the score?
No. Age is stored only for the report. The score depends on specific clinical findings, recent immobility or surgery, cancer, prior DVT, and the alternative diagnosis item.
3. Why does one criterion subtract points?
The rule lowers DVT probability when another diagnosis appears at least as likely. Examples may include cellulitis, Baker’s cyst, muscle injury, or superficial vein inflammation.
4. How is calf difference handled here?
Enter both calf circumferences in centimeters. The calculator auto-marks the criterion when the difference exceeds 3 cm, or you can switch it on manually if assessed clinically.
5. Can a low score exclude DVT?
Not by itself. Lower scores are usually combined with a high-sensitivity D-dimer or ultrasound pathway, depending on symptoms, setting, and local diagnostic protocol.
6. Is this tool suitable for pregnancy or children?
No. Pregnancy and pediatric patients use different diagnostic pathways. This page is intended for adult, nonpregnant clinical pretest assessment support only.
7. Why include the graph?
The graph shows how each criterion changes the running total. That helps with teaching, audit review, documentation clarity, and quick explanation of the final category.
8. What are the export buttons for?
They generate a quick report for handoff, audit, teaching, or chart drafting. The export is a convenience tool, not a replacement for formal medical documentation.