If a test is 99% sensitive, what does this imply about its effectiveness?

When a test is described as having 99% sensitivity, it indicates that the test is highly effective in correctly identifying individuals who have the condition in question. Specifically, sensitivity refers to the ability of the test to correctly detect positive cases. Therefore, if a test has 99% sensitivity, it means that out of 100 people who actually have the condition, 99 will be correctly identified as having it by the test. This high degree of sensitivity is essential, especially in clinical settings where missing a diagnosis could lead to significant health consequences.

The other options do not accurately represent the meaning of sensitivity. For example, while false negatives and effectiveness implications are related concepts, they do not accurately reflect the definition of sensitivity in this case. The focus on the test's ability to correctly identify those with the condition is key to understanding the significance of a high sensitivity percentage. This is why option B succinctly and accurately captures the essence of what a 99% sensitivity implies about the effectiveness of the test.