Wells Score Calculator for Pulmonary Embolism
The pretest probability score that decides whether your chest pain or dyspnea patient needs a D-dimer, a CT angiogram, or neither.
How to actually use it
Use the two-tier cut: 4 or less is "PE unlikely," and a negative D-dimer in that group ends the workup without imaging. Above 4 is "PE likely," and that patient goes to CT angiography; a D-dimer adds nothing because you are scanning regardless of the result. Ordering the D-dimer on a high-probability patient is the classic backwards move: a positive changes nothing and a negative is not reassuring enough to stop.
The most heavily weighted item, "PE is the most likely diagnosis," is subjective by design: the score formalizes your gestalt rather than replacing it. Age-adjusted D-dimer thresholds (age times 10 in patients over 50, with the usual assay caveats) rescue specificity in older patients. The decision tree, and what to do when the CT is positive, is walked through in the pulmonary rotation guide; anticoagulation choices live in the heparin drip guide and the warfarin guide, and prevention in DVT prophylaxis.
This is not medical advice. Educational tool. Pretest probability scores only work when applied before the testing they are meant to gate. Institutional pathways and current references govern.