A tuberculin skin test is done to find people who have 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 unexplained weight loss.
• People who have had an abnormal chest X-ray.
• People who have had a recent organ transplant or have an impaired immune system, such as those with human immunodeficiency virus (HIV).

A tuberculin skin test should not be done for people:

• With a known TB infection.
• Who have had a previous severe reaction to the TB antigens.
• Who have a skin rash that would make it hard to read the skin test.

• Do not scratch the test site. Scratching it may cause redness or swelling. This could affect the test results.
• To ease itching, put a cold washcloth on the site. Then pat the site dry.
• Do not cover the test site with a bandage or other dressing.