What does "sensitivity" in diagnostic testing refer to?

Sensitivity in diagnostic testing is defined as the probability of correctly identifying individuals who have a specific disease, meaning it measures the test's ability to detect the disease when it is indeed present in the patient. High sensitivity indicates that the test is effective at identifying true positives, thereby minimizing the chance of a false negative result—where the test fails to detect the disease in an affected individual. This characteristic is crucial in screening tests where missing a diagnosis could have significant clinical implications.

Understanding sensitivity helps healthcare professionals choose appropriate diagnostic tests based on the clinical context. For instance, in conditions where early detection is critical, a test with high sensitivity would be preferred to ensure that as many cases as possible are identified and managed. While accuracy, avoidance of false positives, and likelihood of negative results are important aspects of diagnostic tests, they relate differently to how well a test identifies true positive cases of a disease.