What do we call the probability of a positive result if a patient has the disease?

The probability of a positive result if a patient has the disease is referred to as sensitivity. Sensitivity measures the ability of a test to correctly identify individuals who have a specific disease or condition. It is calculated as the proportion of true positives (individuals correctly identified as having the disease) out of the total number of individuals who actually have the disease (true positives plus false negatives). High sensitivity indicates that the test is effective in detecting the presence of the disease, minimizing the chances of false negatives.

In contrast, specificity relates to the ability of a test to correctly identify those without the disease, while negative predictive value involves the probability that individuals with a negative test result truly do not have the disease. Prevalence refers to how common the disease is in a given population at a certain time and does not pertain to the accuracy of a diagnostic test. Understanding these definitions helps clarify why sensitivity is the correct term for the probability of a positive result in patients who have the disease.