Tuberculosis (TB) is an airborne infectious disease caused by the bacteria Mycobacterium tuberculosis. The two most common types of tests to screen for this disease are the Mantoux PPD tuberculin skin test, which is generally considered the most reliable, and the TB tine test. A diagnosis of tuberculosis is never made based on the results of a TB skin test, but requires further testing including a sputum culture and a chest x ray.

Because TB is spread through the air, especially in poorly ventilated areas, it is more commonly found among people living in crowded conditions, such as jails, nursing homes, and homeless shelters. Often, a TB skin test will be given as part of a physical examination when a person is hiring a new employee, particularly for those individuals seeking employment in the healthcare or food service professions.

People can be exposed to...