Tuberculosis Screening Services

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TB Screening FAQ

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Unfortunately, CDPH no longer provides routine TB screening services to the public. Many health clinics and doctor’s offices in Chicago can test someone for TB; for a list of some of the places in Chicago, please review these TB Screening Locations in Chicago. CDPH recommends that members of the public who require TB screening contact these clinics directly to verify availability and cost of TB screening.

A skin test or TB blood test can be used to help detect TB in a person. The skin test is performed by injecting a small amount of fluid (called tuberculin) under the skin, usually on the lower part of your arm. The results of the test are read 48 to 72 hours after the test, by a trained healthcare worker. A TB blood test is performed by drawing blood from a person and sending it to a lab for testing.  


A positive test tells us that a person is infected with TB germs, but it does not necessarily mean that you have TB disease. A person can be infected with MTB that is not causing illness. This is called “latent TB infection” or LTBI.

If you have a positive test, further medical evaluation and testing, such as a chest x-ray, reviewing medical history or other labs tests is needed to make sure you do not have TB disease. TB disease is treated by taking several drugs as recommended by a health care provider.

A person with latent TB infection is not contagious at all. A person with LTBI is at risk of developing the illness TB (about 5-10% over a person’s lifetime). LTBI can be treated to make sure that you never develop active TB disease.

Many countries in the world routinely administer BCG vaccine. BCG does not prevent a person from becoming infected with TB or developing TB disease. If you received BCG vaccine, a blood test may be more accurate than a TB skin test.

People with low risk of infections generally do not need regular screenings for TB. However, certain individuals should be tested regularly. According to the CDC, this includes:

  • People who have spent time with someone who has TB disease
  • People with HIV infection or another medical problem that weakens the immune system
  • People who have symptoms of TB disease (fever, night sweats, cough, and weight loss)
  • People from a country where TB disease is common (most countries in Latin America, the Caribbean, Africa, Asia, Eastern Europe, and Russia)
  • People who live or work somewhere in the United States where TB disease is more common (homeless shelters, prison or jails, or some nursing homes)
  • People who use illegal drugs

For more information about TB, you can visit the Centers for Disease Control and Prevention website.