The results of the TB skin test are read between 48 and 72 hours after the injection. The test assesses the size of the raised, red bump (or induration) that appears at the injection site. A small or absent bump typically indicates no exposure to the TB bacterium.
Conversely, a large bump may suggest a past or present infection. However, a positive result does not necessarily mean you have active TB disease; additional testing, such as a chest X-ray or sputum test, is usually required to confirm the diagnosis.
