Preview The incidence of tuberculosis in the United States is escalating at an alarming rate. Thus, it is imperative to detect the infection early so that chemoprophylaxis can be given before active disease has a chance to develop. The tuberculin skin test is simple, cheap, and effective and should be an integral part of evaluating not only high-risk groups but also the population at large. Dr Amin describes how to administer the test and interpret its results.