Rule-In vs Rule-Out Labs (NP edition 🧠🩺) Not all labs are created equal—and ordering everything isn’t diagnostic reasoning. Rule-OUT labs These help you exclude dangerous or likely diagnoses. 👉 High sensitivity 👉 A negative result is what you’re looking for 👉 Asked when you’re thinking: “What can’t I miss?” Examples: • D-dimer to rule out PE (low risk patient) • Troponin to rule out ACS • Pregnancy test to rule out ectopic before imaging Rule-IN labs These help you confirm a diagnosis you a