🦵 Lower-Extremity DVT Diagnostic Pathway (Wells + D-dimer)
This tool applies the two-level Wells score and D-dimer to direct the next diagnostic step for suspected lower-extremity DVT.
Lower-Extremity DVT Diagnostic Pathway (Wells + D-dimer)
Wells clinical probability
D-dimer (when unlikely)
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
Decision support for licensed clinicians only; not a substitute for clinical judgement, diagnosis or local protocols.