In medicine and statistics, sensitivity and specificity mathematically describe the accuracy of a test that reports the presence or absence of a medical condition. If individuals who have the condition are considered "positive" and those who do not are considered "negative", then sensitivity is a measure of how well a test can identify true positives and specificity is a measure of how well a test can identify true negatives:Sensitivity is the probability of a positive test result, conditioned on the individual truly being positive. Specificity is the probability of a negative test result, conditioned on the individual truly being negative.