The tuberculosis skin test is a test used to determine if someone has developed an immune response to the bacterium that causes tuberculosis (TB). This response can occur if someone currently has TB, if they were exposed to it in the past, or if they received the BCG vaccine against TB.
The tuberculosis skin test is also known as the tuberculin test or PPD test. The PPD test is used to determine if someone has developed an immune response to the bacterium that causes tuberculosis (TB).
The basis of the reading of the skin test is the presence or absence and the amount of induration (localized swelling). A negative test does not always mean that a person is free of tuberculosis. A person who received a BCG vaccine against tuberculosis may also have a positive skin reaction to the TB test.
