Sensitivity and specificity are the probability of a correct test result in subjects with and without a condition, respectively.
Sensitivity (true positive fraction, TPF) measures the ability of a test to detect the condition when it is present. It is the probability that the test result is positive when the condition is present.
Specificity (true negative fraction, TNF) measures the ability of a test to detect the absence of the condition when it is not present. It is the probability that the test result is negative when the condition is absent.
