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Screenings

Latent tuberculosis screening

Latent tuberculosis causes no symptoms, but without treatment about 5% to 10% of healthy people with it go on to active TB disease. The USPSTF gives screening a grade B for adults at increased risk. (USPSTF, 2023)

USPSTF grade
B
Who
Adults at increased risk
Ages
18 and older
How often
See below

When it starts, when it can stop

Who it is for

Adults 18 or older without symptoms who are at increased risk for tuberculosis. (USPSTF, 2023)

In My Screening Plan this shows under "Also ask your doctor about" for everyone in the age range. The planner does not ask about these risk factors, so nothing about them is entered or stored.

Test and how often

  • A tuberculin skin test (TST), read 48 to 72 hours later, or an interferon-gamma release assay (IGRA) blood test. (USPSTF, 2023)
  • How often depends on risk: from one time for people unlikely to be exposed again, to every year for people at continued risk of exposure. (USPSTF, 2023)
  • People who test positive need more tests, such as a chest X-ray, and treatment to get the benefit. (USPSTF, 2023)

TB skin test or TB blood test

The two latent TB tests used in the US
TB skin test (TST)TB blood test (IGRA)
How it is doneTesting material is put under the skin with a small needleOne blood sample
VisitsA return visit 2 to 3 days later to read it (48 to 72 hours)One visit; the lab processes the sample
After the BCG vaccineThe result can be affectedNot affected; preferred by the CDC

Both tests are used in the US. The skin test needs a trained person to give it and to read it 48 to 72 hours later; the blood test needs one blood draw. (USPSTF, 2023)

The CDC says the blood test is the preferred test for people who have had the TB vaccine (BCG), and that the skin test means returning to your provider 2 to 3 days later. (CDC, 2024)

How often to test depends on risk. The USPSTF found no evidence on the best interval and describes a range from one test for people at low risk of future exposure to a test every year for people at continued risk. The recommendation is for adults 18 and older. (USPSTF, 2023)

Ask your doctor which test fits you.

Questions people ask

Who should get a TB test?

The USPSTF names people who were born in, or used to live in, countries where TB is common, and people who live or have lived in high-risk group settings such as homeless shelters or correctional facilities. Local health departments can say which groups are at risk in your area. (USPSTF, 2023)

Skin test or blood test?

Both are available in the US: the tuberculin skin test, which a trained person reads 48 to 72 hours later, and the IGRA blood test. (USPSTF, 2023)

Does this apply if I have a cough or other symptoms?

No. The recommendation is for adults without symptoms. Anyone with symptoms of TB should see a clinician for diagnosis, not screening. (USPSTF, 2023)

Does the BCG vaccine affect a TB test?

It can affect the skin test. The CDC says the TB blood test is the preferred test for people who have had the BCG vaccine. (CDC, 2024)

How often should you get a TB test?

It depends on your risk. The USPSTF says one test may be enough for people at low risk of future exposure, and a yearly test may make sense for people at continued risk. (USPSTF, 2023)

Who else should get tested for TB?

Besides the groups the USPSTF names, the CDC lists recent contacts of a person with active TB and health care workers among people at higher risk of exposure who should get tested. (CDC, 2024)

Source

U.S. Preventive Services Task Force, "Latent Tuberculosis Infection in Adults: Screening", final recommendation released May 2, 2023. Read it on uspreventiveservicestaskforce.org. Checked against the live page on 2026-10-28.

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