Specificity rules IN means what?

Specificity rules IN means what?

• A. A negative result rules in disease
• B. A positive result rules in disease
• C. A positive result rules out disease
• D. It applies only to prevalence

Answer: (B)

Specificity is about correctly identifying people who do not have the disease. A highly specific test yields very few false positives. Because of that, when the test result is positive, it provides strong evidence that the disease is present, so we say a positive result rules in disease. In contrast, sensitivity relates to ruling out disease with a negative result (a highly sensitive test, when negative, makes you confident the disease is not there). Remember that the exact usefulness of a positive result also depends on disease prevalence, but the core idea is that high specificity makes positive results reliable for confirming disease.

Specificity is about correctly identifying people who do not have the disease. A highly specific test yields very few false positives. Because of that, when the test result is positive, it provides strong evidence that the disease is present, so we say a positive result rules in disease. In contrast, sensitivity relates to ruling out disease with a negative result (a highly sensitive test, when negative, makes you confident the disease is not there). Remember that the exact usefulness of a positive result also depends on disease prevalence, but the core idea is that high specificity makes positive results reliable for confirming disease.