Tuberculosis Screening

Tuberculosis (TB) Screening

Tuberculosis (TB) can be an infectious and potentially deadly disease caused by the bacteria Mycobacterium tuberculosis. People who have TB may spread the disease to other people through the air. For this reason, it is important to have routine TB screenings.

Preparation for a TB Screening

TB screenings generally require no special preparation. A doctor may ask questions about a person’s medical history, as well as whether someone has recently traveled to an area known to have TB. The doctor may also ask about any contact that the person has had with people who have the disease.


The TB screening process typically involves a visit to a doctor’s office, an urgent care clinic or a hospital. A doctor or a nurse may first ask questions to evaluate the person’s risk of TB. A physical examination may also be done. If an infection is suspected, a skin or blood test may be ordered.

Types of Tests

TB testing typically involves skin or blood tests.

  • Skin tests – A nurse may inject a small amount of a harmless solution containing parts of TB bacteria under the person’s outer layer of skin. After two or three days, the site is checked for any reaction. Such a reaction shows that the body is fighting the bacteria.
  • Blood tests – Blood tests, such as interferon-gamma release assays (IGRA), are sometimes used instead of skin tests to detect the body’s immune response to TB bacteria. A positive result typically means that a person has TB, but further tests are needed to confirm the diagnosis.


TB screening tests are generally safe and are not known to cause any serious side effects. There may be some soreness, swelling, or redness at the site of a skin test.

Why TB Screening Is Important

Tuberculosis can be difficult to diagnose, especially in the early stages. As such, routine screening is important for early detection and treatment of TB. This can help stop the spread of the disease to others. It is especially important for people with a higher risk of infection, such as those who travel in parts of the world where TB is more common, Healthcare workers, and people who live or work in places with large numbers of people.

When to Have a TB Screening

Most people don’t need to have a TB screening test unless they have symptoms of TB or have been exposed to someone with the disease. People who are at a higher risk of TB infection may need to have TB screenings more often. People with active TB need to take specific antibiotics for at least six months or longer, often after a positive TB skin test, to get rid of the bacteria and prevent the spread of the disease.