The tuberculosis blood test is a screening test that can show if your child has been infected with tuberculosis (TB) bacteria. The test is called an Interferon Gamma Release Assay or IGRA.
TB is spread through the air from person to person. It usually causes lung disease, although it can affect almost any part of the body. An active TB infection can be a very serious illness. The TB blood test can find most TB infections before the infection is serious enough to cause any problems. TB infections are no longer common in the US.
Your child should get tested if he:
Usually no preparation is needed for this test.
Having this test will take just a few minutes. A small amount of blood is taken from a vein in your child’s arm with a needle. The blood is collected in tubes and sent to a lab.
Ask your healthcare provider when and how you will get the result of your child’s test.
A positive result does not always mean your child has an active TB infection. It may mean that your child was exposed and infected with TB in the past, but his body’s immune system is keeping the bacteria under control.
A negative result usually means that your child does not have TB.
Test results are only one part of a larger picture that takes into account your child’s medical history, physical exam, and current health. Sometimes a test needs to be repeated to check the first result. Talk to your healthcare provider about the result and ask questions such as:
If the test is positive, close family members should be tested.