TB screening is used to look for TB in a skin or blood sample. There are two types of tests for TB infection: the TB skin test and the TB blood test. Factors in selecting which test to use include the reason for testing, test availability, and cost.
TB Skin Test
The TB skin test is also called the Mantoux tuberculin skin test (TST). A TB skin test requires two visits with a nurse, 48-72 hours apart. The test is administered with a needle between the layers of skin and the result depends on the size of the raised, hard area or swelling at the injection site.
TB Blood Test
Two TB blood tests are approved by the U.S. Food and Drug Administration (FDA) and are available in the United States: The QuantiFERON®-TB Gold Plus (QFT-Plus) and the T-SPOT®.TB test (T-Spot). A nurse will draw your blood and send it to a laboratory for analysis and results. TB blood tests only require one appointment with a nurse.