ABSTRACT
Among tests presently used in clinical medicine, the tuberculin skin test is one of the few that was developed in the last century. Given such a long history of use it may seem surprising that the interpretation of this test remains controversial. However, this reflects the changing epidemiology, clinical features, investigation, and management of tuberculosis. In industrialized countries new problems have arisen in the interpretation of the tuberculin skin test in certain high-risk populations because of aging, HIV infection, intravenous (IV) drug use, and other phenomena.
