Which statement about sensitivity is correct?

Which statement about sensitivity is correct?

• A. It reflects the proportion of positive test results that are true positives
• B. It reflects the proportion of true negatives among those tested
• C. It reflects the percentage of false positives
• D. It reflects the proportion of true positives among those who have the disease

Answer: (D)

Sensitivity is the true positive rate: it tells you how good the test is at identifying people who actually have the disease. Specifically, it is the proportion of those with the disease who test positive (TP divided by TP plus FN). This focuses on detection among the truly diseased, not on the accuracy of positive results or on negatives. It’s not the proportion of positive results that are true positives (that would be predictive value), and it’s not about true negatives (that relates to specificity), nor about false positives (which is the false positive rate).

Sensitivity is the true positive rate: it tells you how good the test is at identifying people who actually have the disease. Specifically, it is the proportion of those with the disease who test positive (TP divided by TP plus FN). This focuses on detection among the truly diseased, not on the accuracy of positive results or on negatives. It’s not the proportion of positive results that are true positives (that would be predictive value), and it’s not about true negatives (that relates to specificity), nor about false positives (which is the false positive rate).