🦵 Lower-Extremity DVT Diagnostic Pathway (Wells + D-dimer)
UseUse to decide between D-dimer, compression ultrasound, and exclusion, recognizing that a 'likely' Wells goes …
Loading calculator…
SourceLim W, et al. American Society of Hematology 2018 guidelines for management of VTE: diagnosis of VT…
Runs locally in your browser (no PHI uploaded). For licensed clinicians — not a substitute for clinical judgement.
Stored on this device for revisit reminders
This-shift next steps
After scoring: open the scene pack, peer scores, and the matching pathway. Local reference — no HIS write.
- Who it is for
- Adult medical inpatients who need a VTE risk assessment. Suspected DVT follows the diagnostic path only; this page does not make prophylaxis decisions.
- Who it is not for
- Treatment duration for confirmed VTE is not this prophylaxis card. Acute PE is not handled on the prophylaxis card.
- Formula and variables
- Padua is the entry for medical VTE risk assessment. IMPROVE bleed assesses bleeding risk. Caprini is the surgical entry. IMPROVE VTE does not replace Padua. Wells DVT serves only the diagnostic path. Thresholds stay as on this page. The formula is not changed.
- Result → next step
- Diagnostic pathway. This page does not involve prophylaxis decisions and gives no medication or dose information. Medical VTE risk assessment is on the Padua page.No numeric dose until age, weight, renal function, and pregnancy are all known. Pregnancy is contraindication or caution only.
- Guideline
- China PTE guideline 2018
Score + version; reference only — not a substitute for care · no HIS write
Paste the link in Slack, Teams, X, or LinkedIn — the preview image comes from this page’s Open Graph card.
Methodology · worked example, guidelines & full notes
Clinical takeaway
D-dimer can only exclude DVT when clinical probability is low or intermediate; at high probability ultrasound is mandatory. (original synthesis · not guideline verbatim)
When to use
Use to decide between D-dimer, compression ultrasound, and exclusion, recognizing that a 'likely' Wells goes straight to ultrasound.
How it works
Wells ≤ 1 (unlikely): D-dimer; negative excludes, positive → CUS. Wells ≥ 2 (likely): CUS directly. Proximal-only negative CUS → 1-week repeat or whole-leg ultrasound. Cancer → ultrasound directly.
Key points
- D-dimer can only exclude DVT when clinical probability is low or intermediate; at high probability ultrasound is mandatory. (original synthesis · not guideline verbatim)
- A negative proximal-only ultrasound needs a 1-week repeat to catch distal-to-proximal extension.
- Cancer patients bypass D-dimer because of its poor specificity.
References
Worked calculation
The values below come from this tool's own example placeholders and are computed server-side with the formula shown on this page, so the arithmetic can be checked quickly. It demonstrates how to substitute values only — it is not clinical advice and not a real case.
| Wells clinical probability | DVT unlikely (Wells ≤ 1) |
|---|---|
| D-dimer (when unlikely) | Negative (< threshold) |
→Next stepDVT excluded
- Pathway：DVT unlikely (Wells ≤ 1) + negative high-sensitivity D-dimer: DVT can be excluded without imaging; the 3-month thromboembolic event rate is very low
- D-dimer：High-sensitivity D-dimer < 500 ng/mL (or age-adjusted threshold) with low/intermediate probability can exclude; cannot be used for exclusion at high probability
- Ultrasound：Proximal compression ultrasound has high sensitivity/specificity; a proximal-only negative needs a 1-week repeat to catch distal-to-proximal extension, or a one-time whole-leg ultrasound
| Wells clinical probability | DVT unlikely (Wells ≤ 1) |
|---|---|
| D-dimer (when unlikely) | Not tested/not applicable |
→Next stepTest D-dimer first
- Pathway：DVT unlikely (Wells ≤ 1): test high-sensitivity D-dimer first (age-adjusted threshold usable). Negative excludes, positive prompts compression ultrasound
- D-dimer：High-sensitivity D-dimer < 500 ng/mL (or age-adjusted threshold) with low/intermediate probability can exclude; cannot be used for exclusion at high probability
- Ultrasound：Proximal compression ultrasound has high sensitivity/specificity; a proximal-only negative needs a 1-week repeat to catch distal-to-proximal extension, or a one-time whole-leg ultrasound
Verification & sources · governance
FAQ
Frequently asked questions
- What are the limits and cautions when using Lower-Extremity DVT Diagnostic Pathway (Wells + D-dimer)?
- For licensed clinicians and clinical researchers. Interpret results with history, investigations and local protocols; not a diagnosis or prescription, and not a substitute for multidisciplinary decision-making or local guidelines.
- Does Lower-Extremity DVT Diagnostic Pathway (Wells + D-dimer) upload patient data? Where is it calculated?
- Calculation runs locally in the browser; inputs and results are not uploaded. For licensed clinicians only; interpret with history, investigations and local protocols — not a diagnosis or prescription.
- How is Lower-Extremity DVT Diagnostic Pathway (Wells + D-dimer) calculated in practice? Can you show a worked example?
- Inputs: Wells clinical probability DVT unlikely (Wells ≤ 1), D-dimer (when unlikely) Negative (< threshold) → Result: Next step DVT excluded（Pathway: DVT unlikely (Wells ≤ 1) + negative high-sensitivity D-dimer: DVT can be excluded without imaging; the 3-month thromboembolic event rate is very low, D-dimer: High-sensitivity D-dimer < 500 ng/mL (or age-adjusted threshold) with low/intermediate probability can exclude; cannot be used for exclusion at high probability, Ultrasound: Proximal compression ultrasound has high sensitivity/specificity; a proximal-only negative needs a 1-week repeat to catch distal-to-proximal extension, or a one-time whole-leg ultrasound） Inputs: Wells clinical probability DVT unlikely (Wells ≤ 1), D-dimer (when unlikely) Not tested/not applicable → Result: Next step Test D-dimer first（Pathway: DVT unlikely (Wells ≤ 1): test high-sensitivity D-dimer first (age-adjusted threshold usable). Negative excludes, positive prompts compression ultrasound, D-dimer: High-sensitivity D-dimer < 500 ng/mL (or age-adjusted threshold) with low/intermediate probability can exclude; cannot be used for exclusion at high probability, Ultrasound: Proximal compression ultrasound has high sensitivity/specificity; a proximal-only negative needs a 1-week repeat to catch distal-to-proximal extension, or a one-time whole-leg ultrasound）