When aiming to rule out a disease, which test property should be prioritized?

• A. High specificity.
• B. High sensitivity.
• C. High positive predictive value.
• D. High negative predictive value.

Answer: (B)

Ruling out disease hinges on avoiding false negatives. A test with high sensitivity correctly identifies most people who have the disease, so a negative result strongly suggests absence of disease. This idea is often summarized as SnNout: with high sensitivity, a negative test rule-outs disease. Specificity affects what happens after a positive result (helpful for ruling in), while predictive values depend on how common the disease is in the population and are not as reliable for making a ruling based on a single negative result. So prioritizing high sensitivity best supports confidently ruling out disease.