In disease testing, what is meant by "specificity"?

Specificity refers to the ability of a test to correctly identify individuals who do not have a particular disease. In other words, it assesses the test's accuracy in ruling out those who are healthy. High specificity means that when the test indicates a negative result, there is a high likelihood that the individual truly does not have the disease, leading to fewer false positives. This is crucial in disease testing as it helps ensure that healthy individuals are not mistakenly diagnosed as having a disease, which could lead to unnecessary anxiety and potential treatment.

The focus of specificity is distinct from sensitivity, which measures how well a test can identify individuals who do have the disease. Understanding these terms is fundamental in evaluating the effectiveness of diagnostic tests and their role in public health.