What are sensitivity and specificity?

Sensitivity and specificity are terms used to estimate the accuracy of test results.

Sensitivity refers to the probability of testing positive for a disease if the disease is truly present. As the sensitivity of a test increases, the number of people who have the disease but test negative (false negatives) will decrease.

Specificity refers to the probability of testing negative if the disease is truly absent. As the specificity of a test increases, the number of people who do not have the disease but test positive (false positives) will decrease.

When describing clinical tests, doctors and researchers often use the terms sensitivity and specificity. These are statistical measures of how well the test performs. Sensitivity reflects the percentage of time the test results are positive  in people who actually have the disease or condition. Specificity reflects the percentage of time the test results are negative  in those who do not have the disease or condition.