Wells Criteria for DVT
Estimates pre-test probability of deep vein thrombosis
How to use & interpret
The Wells score for DVT sets the pre-test probability of a lower-limb deep vein thrombosis to choose the next test. Using the two-tier version: 'DVT unlikely' (≤1) allows a D-dimer — if negative, DVT is excluded; 'DVT likely' (≥2) should proceed to proximal leg vein ultrasound.
Subtract a point if an alternative diagnosis is at least as likely. As with PE, an age-adjusted D-dimer can reduce unnecessary scanning in older 'unlikely' patients. The score guides testing; it does not diagnose or exclude DVT by itself.
Score interpretation
Score ≤0: ~5% DVT probability
→ D-dimer; if negative, DVT excluded
Score 1–2: ~17% DVT probability
→ D-dimer; if positive or intermediate, duplex ultrasound
Score ≥3: ~53% DVT probability
→ Duplex ultrasound without waiting for D-dimer; consider anticoagulation
Interpretation bands for the Wells DVT. Apply clinical judgement and local guidance.
Frequently asked questions
What if the D-dimer is negative but suspicion stays high?
A negative D-dimer only excludes DVT in 'unlikely' patients. If clinical suspicion is high, proceed to ultrasound regardless, and consider repeat imaging at 1 week if the first scan is negative.
References
- Wells PS, et al. Value of assessment of pretest probability of deep-vein thrombosis in clinical management. Lancet. 1997;350(9094):1795–8.
Related
Curated clinical cross-links plus same-class fallbacks.
- HERDOO2 Rule for Discontinuing Anticoagulation in Unprovoked VTE · Venous Thromboembolism
- RIETE Score for Bleeding Risk in VTE · Venous Thromboembolism
- Wells Criteria for PE · Venous Thromboembolism
- PERC Rule for PE · Venous Thromboembolism
- Revised Geneva Score for PE · Venous Thromboembolism
- Wells DVT Score · Venous Thromboembolism
- Difficult Airway Algorithm (DAS) · DAS 2015; Royal College of Anaesthetists
- Major Haemorrhage Protocol · NICE NG24; UK MHP guidelines
- New-Onset Atrial Fibrillation · ESC 2020 AF Guidelines; NICE NG196
- Hypertensive Emergency · ESC/ESH 2018 Hypertension Guidelines; NICE NG136
- Bradycardia Management · Resuscitation Council UK ABCDE; ESC 2021 Pacing Guidelines
Featured in these MRCEM clinical pathways
The Wells DVT is covered in detail — with RCEM/NICE evidence base, indications and pitfalls — in the following exam-focused pathways on our sister siteReviseMRCEM.
MRCEM Primary / Intermediate / OSCE candidates: each pathway includes exam-style questions, RCEM/NICE citations, and FAQ summaries.
Decision support only — verify against a current formulary, NICE, or your local guideline before clinical use.