The Wells score estimates the pre-test probability of pulmonary embolism. It guides the decision to perform D-dimer testing vs. direct CT pulmonary angiography. Score updates live as you check criteria.
Reference Table
| Score | 2-Tier | 3-Tier | PE Prevalence | Next Step |
|---|
| ≤4 | PE Unlikely | — | ~8% | D-dimer |
| >4 | PE Likely | — | ~28% | CTPA |
| <2 | — | Low | 1.3% | D-dimer |
| 2–6 | — | Moderate | 16.2% | D-dimer or CTPA |
| >6 | — | High | 37.5% | CTPA |
Clinical Notes
Consider using the PERC Rule if Wells ≤4 and pre-test probability is low — a negative PERC may allow PE exclusion without D-dimer testing.
A negative high-sensitivity D-dimer with Wells ≤4 effectively rules out PE (negative predictive value >99%). If D-dimer is positive or Wells >4, proceed to CTPA.
For educational use only. Not a substitute for clinical judgment.
