Latent tuberculosis tests

Your child may have tests to find out if your child has latent tuberculosis (TB). Children with latent TB have the TB bacteria in their bodies. But they don't have any symptoms of TB. The tests may include the tuberculin skin test or the interferon-gamma release assay (IGRA) blood test.

If your child has been in close contact with someone who has TB, your child could be infected. Tests help your doctor find a latent (inactive) TB infection. Then your child can get treatment if needed. This can prevent latent TB from becoming active TB disease that can spread to other people.

Your child may get the tuberculin skin test or the interferon-gamma release assay (IGRA) blood test. The skin test is often used in children younger than 5 years old.

During the skin test, part of a TB bacterium is injected under your child's skin. The test feels like a quick needle poke.

For the blood test, your child's blood is taken by a health professional. It is then tested in a lab.

If the doctor suggests a TB skin test for your child, tell the doctor if your child has had the BCG vaccine. It interferes with skin test results. People who get the BCG vaccine are likely to have TB test results that show they have a TB infection even when they don't.