Diagnostic specificity describes the test's ability to correctly identify those without the disease. Which term corresponds to this concept?

• A. Sensitivity
• B. Specificity
• C. Predictive value
• D. Accuracy

Answer: (B)

This question is about how well a test avoids mislabeling healthy people as diseased. The term that captures this ability is specificity. Specificity is the proportion of true negatives among all individuals without the disease. A highly specific test yields few false positives, meaning that when the disease is not present, it is very likely to produce a negative result.

For example, if 100 people are disease-free and the test correctly returns negative for 95 of them but wrongly flags 5 as positive, the specificity is 95%. By contrast, sensitivity looks at those who actually have the disease and measures how well the test identifies them as positive. Predictive value relates to how likely a test result reflects actual disease status given prevalence, and accuracy is the overall rate of correct results across all people.