What does specificity in a medical test represent?

Specificity in a medical test is a measure of the test's ability to correctly identify those who do not have the disease. When a test is described as having high specificity, it means that when the result is negative, it is quite unlikely that the person actually has the disease. Essentially, a negative result indicates that the individual is free from the condition, which is critical for reducing false positives; those who do not have the disease are correctly identified as such.

Understanding this concept is vital in clinical practice, as high specificity is desirable for screening tests where it is important to minimize the number of healthy individuals incorrectly diagnosed with a disease (false positives). By ensuring that the test is reliable in ruling out the disease in healthy individuals, it allows healthcare providers to focus on those who may genuinely need further testing or treatment.