The tuberculin skin test determines if you have been infected with tuberculosis (TB). Not all people who have been exposed to TB exhibit symptoms, so it is important to know if you have an active case and can spread the disease to others.

A small amount of tuberculosis antigen is injected under your skin. If a hard, red, raised bump appears, it indicates that you have been exposed to TB. Further testing may be necessary if you are exhibiting symptoms of TB.