In imaging test performance, what does sensitivity refer to?

In imaging test performance, what does sensitivity refer to?

• A. The ability to detect disease when it is present
• B. The ability to correctly identify those without disease
• C. The speed of the imaging test
• D. The cost-effectiveness of screening

Answer: (A)

Sensitivity measures how good an imaging test is at detecting disease when it is actually present. It is the true positive rate—among all individuals who truly have the disease, what fraction test positive? A test with high sensitivity will miss few cases, minimizing false negatives. For example, if 100 people with the disease are tested and 92 test positive, the sensitivity is 92%. This is especially important in screening, where you want to catch as many real cases as possible. The other ideas—speed of the test, cost-effectiveness, or correctly identifying those without disease—do not describe sensitivity. Speed is about how fast the test runs, cost-effectiveness about economics, and correctly identifying non-diseased individuals relates to specificity (the true negative rate).

Sensitivity measures how good an imaging test is at detecting disease when it is actually present. It is the true positive rate—among all individuals who truly have the disease, what fraction test positive? A test with high sensitivity will miss few cases, minimizing false negatives. For example, if 100 people with the disease are tested and 92 test positive, the sensitivity is 92%. This is especially important in screening, where you want to catch as many real cases as possible. The other ideas—speed of the test, cost-effectiveness, or correctly identifying those without disease—do not describe sensitivity. Speed is about how fast the test runs, cost-effectiveness about economics, and correctly identifying non-diseased individuals relates to specificity (the true negative rate).