The tool to measure the presence of a tuberculous infection is the tuberculin skin test.
Because tuberculous infection is central to our understanding of the dynamics of the epidemic, it will be necessary to learn more about tuberculin and the tuberculin test.
While desirable, it is not possible in practice to measure the incidence of tuberculous infection in a community. First, a large number of people would have to be tested frequently, every year or so. Second, repeat tuberculin skin testing in the same person can cause difficulties in the interpretation of the test. We will thus first introduce the tuberculin test and then discuss the prevalence of tuberculous infection in different populations and population segments.