Laboratory role in tuberculosis control.

The term "tuberculosis" (TB) refers to infection with the bacterium Mycobacterium tuberculosis that has progressed to active disease. This disease is a public health threat because it is caused by a microorganism that is potentially fatal for humans, and transmission is commonly through the inhalation of airborne droplets expelled by infectious persons with active disease. The World Health Organization (WHO) estimates that there are more than 8 million new cases of TB each year, 2 million deaths from the disease each year, and that one-third of the world population is infected with M. tuberculosis and at risk for active disease. In 2003, the 100-year anniversary of the founding of the Wisconsin State Laboratory of Hygiene (WSLH), TB is recognized as a disease that is preventable and now almost always treatable. An early and accurate diagnosis of TB is perhaps the most significant intervention step in TB control. Early diagnosis permits expedited treatment and limitation of spread. An effective TB laboratory program plays an essential role in the early and accurate diagnosis and appropriate treatment of TB. This article examines that role.