Doctor examining and comparing the X–ray of the lungs of an healthy patient (right) with those of a patient affected by tuberculosis. The diseased lungs appear covered with dense opacities marking the infected sites.
A tuberculin skin test is done to find people with tuberculosis (TB), including:
- People who have been in close contact with someone known to have TB.
- Health care workers who are likely to be exposed to TB.
- People with TB symptoms, such as an ongoing cough, night sweats, and weight loss for no reason.
- People who have had an abnormal chest X–ray.
- People who have had a recent organ transplant or with impaired immune systems, such as those with human immunodeficiency virus (HIV).
A tuberculin skin test should not be done for people who have a:
- Known TB infection, Positive tuberculin skin test in the past. A second test may cause a more severe reaction to the TB antigens. Skin rash that would make it hard to read the skin test.