Wells score — Pulmonary embolism probability
PE pre-test probability for D-dimer/CT decision
Mnemonic device
Wells PE score (7 items)
Mapping
Clinical signs of DVT
+3 points
PE more likely than alternative dx
+3 points
HR >100
+1.5 points
Immobilization ≥3 days OR surgery <4 weeks
+1.5 points
Prior DVT/PE
+1.5 points
Hemoptysis
+1 point
Active malignancy
+1 point
Clinical note: Score <2 = low (D-dimer first); 2-6 = moderate (D-dimer or CT); >6 = high (CT directly, skip D-dimer). PERC rule excludes PE in low-pretest-probability patients without further testing. Massive PE = hemodynamic instability + RV strain — consider thrombolysis.