About

Deep Vein Thrombosis (DVT) is a serious condition that can lead to pulmonary embolism if untreated. The Wells Score is the gold-standard clinical prediction rule used to quantify the pre-test probability of DVT before ordering imaging (like Ultrasound) or lab work (D-dimer). This stratification reduces unnecessary testing in low-risk patients while ensuring high-risk patients receive immediate attention.

This tool is designed for rapid clinical use, featuring the standard 10 criteria. It accounts for the crucial subtraction of points when an alternative diagnosis is more likely, a factor often overlooked in manual calculations.

Formulas

The Wells Score is an integer sum. Most positive findings add 1 point, while the presence of a likely alternative diagnosis subtracts 2 points.

Score = 9∑i=1 Criteria_i − (2 if Alternative Dx)

Reference Data

Score Range	Risk Category	Probability of DVT	Clinical Recommendation
3 or more	High Risk	53%	Compression Ultrasonography
1 to 2	Moderate Risk	17%	D-dimer test / Ultrasound
0 or less	Low Risk	5%	D-dimer test to rule out
Dichotomized
≥ 2	Likely	28%	Ultrasound recommended
< 2	Unlikely	6%	D-dimer recommended

Frequently Asked Questions

This refers to clinical scenarios like cellulitis, muscle strain, Baker's cyst, or post-operative swelling that could explain the symptoms just as well as DVT. It is a subjective clinical judgment.

Recent guidelines simplify the result into two groups: "DVT Likely" (Score ≥ 2) and "DVT Unlikely" (Score < 2). This binary approach simplifies the decision tree for ordering D-dimer tests versus immediate imaging.

Asymmetry is key. Swelling must be measured 10cm below the tibial tuberosity and compared to the asymptomatic leg. Generalized swelling (edema in both legs) is usually systemic (e.g., heart failure) rather than DVT.