How is specificity of a screening test defined?

Specificity of a screening test is defined as the ability of the test to correctly identify individuals who do not have the condition being assessed. This means that specificity measures how well the test can distinguish between those individuals who are healthy (or free from the condition) and those who have the condition.

The correct understanding of specificity involves looking at the proportion of people who pass the test and are truly not affected by the condition, which in this context aligns with the identification of individuals who are not aspirators. A high specificity indicates that few healthy individuals are incorrectly identified as having the condition, minimizing false positives.

In contrast, the other options reference varying aspects of test results, such as individuals who fail the test, or those identified as aspirators, which do not accurately reflect the concept of specificity. The clarity in the definition helps to ensure effective screening and accurate identification in clinical practice.