Wells Score (DVT)
DVT Pretest Probability (Wells Score)
≤0 unlikely (D-dimer rules out) · ≥2 likely (ultrasound first).
The board-friendly take on a swollen calf is that imaging is not the first step — Wells score is. Active cancer, paralysis or recent immobilization, recent bedrest 3+ days or surgery within 12 weeks, tenderness along deep veins, entire leg swelling, calf swelling 3 cm greater than asymptomatic side, pitting edema, collateral superficial veins, prior DVT — each scores 1 point; an alternative diagnosis at least as likely subtracts 2. Score 0 or less is unlikely (D-dimer rules out); 1 is moderate; 2 or higher is likely (compression ultrasound first). AANP exam vignettes test the threshold and the right next test based on probability.
- CancerActive cancer (within 6 mo or palliative)+1 point.
- ParalysisParalysis, paresis, or recent plaster immobilization of leg+1 point.
- BedriddenRecently bedridden >3 days or major surgery within 12 weeks+1 point.
- TenderLocalized tenderness along deep venous system+1 point.
- Leg swollenEntire leg swollen+1 point.
- Calf +3cmCalf swelling >3cm vs. asymptomatic leg (10cm below tibial tuberosity)+1 point.
- PittingPitting edema confined to symptomatic leg+1 point.
- CollateralCollateral superficial (non-varicose) veins+1 point.
- Prior DVTPreviously documented DVT+1 point.
- Alt dxAlternative diagnosis at least as likely as DVT−2 points. The only negative item — do not forget it.
Clinical Context
Sorts patients into low-probability ("DVT unlikely," ≤0 or ≤1 depending on 2-tier version) vs. high-probability ("DVT likely," ≥2). Low + negative D-dimer rules out DVT without imaging. High or positive D-dimer → compression ultrasound.
D-dimer alone is sensitive but not specific — use it AFTER risk stratification, not before. Common trap: using D-dimer in a high-pretest-probability patient where a positive result adds nothing and a negative result still requires imaging.
AANP primary-care stem: unilateral calf swelling with tenderness after a long flight — calculate Wells, decide on D-dimer vs. ultrasound. Recent surgery + active cancer + tenderness + unilateral swelling = easily ≥3 and needs imaging, not a D-dimer.
Related Mnemonics
- 5 T's — Cyanotic Congenital Heart Defects
- 6 P's — Acute Limb Ischemia
- CHA₂DS₂-VASc — Stroke Risk in Non-Valvular Atrial Fibrillation
- HAS-BLED — Bleeding Risk on Anticoagulation
- MR. PASS MVP — Systolic Murmurs
Sources
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