Wells Score Calculator
Assess the clinical probability of deep vein thrombosis (DVT) or pulmonary embolism (PE) to guide diagnostic testing and management.
About Wells Score
The Wells criteria are validated clinical prediction rules that estimate the probability of DVT or PE. Combined with D-dimer testing, they guide appropriate use of imaging studies and reduce unnecessary testing while maintaining diagnostic accuracy.
DVT Interpretation
PE Interpretation
Frequently Asked Questions
For patients over 50, use age-adjusted D-dimer cutoff: age × 10 µg/L (e.g., 650 µg/L for a 65-year-old). This increases specificity while maintaining sensitivity. The standard cutoff of 500 µg/L has poor specificity in elderly patients.
The Pulmonary Embolism Rule-out Criteria (PERC) can rule out PE without testing if ALL criteria met: age <50, HR <100, O2 sat ≥95% on room air, no hemoptysis, no estrogen use, no prior VTE, no unilateral leg swelling, no surgery/trauma requiring hospitalization in past 4 weeks. Only apply when clinical suspicion is already low.
Wells criteria are less validated in pregnancy. D-dimer is elevated physiologically and less useful. For suspected DVT, proceed directly to compression ultrasound. For PE, V/Q scan may be preferred over CTPA to reduce breast radiation, though CTPA is acceptable. Clinical assessment remains crucial.
Options include: repeat compression ultrasound in 5-7 days (to catch propagating thrombus), whole-leg ultrasound if only proximal veins were assessed, or alternative imaging (MR or CT venography). Serial testing strategy has <1% false negative rate for clinically significant DVT.
This calculator uses the Modified Wells (simplified) scoring: PE unlikely (≤4) vs PE likely (>4). The original three-tier version (low/moderate/high) is also valid but the two-tier system is more commonly used with current diagnostic algorithms. Both perform similarly in clinical practice.
Clinical Pearls
- Clinical gestalt: "PE most likely" is subjective but validated
- Subsegmental PE: Clinical significance and treatment is debated
- Upper extremity DVT: Wells criteria not validated; use clinical judgment
- Recurrent VTE: Consider alternative diagnoses if on anticoagulation
Medical Disclaimer: This calculator assists clinical decision-making but does not replace clinical judgment. VTE can be life-threatening; always consider the full clinical picture and maintain appropriate suspicion even with low scores.