TB Testing

What is a skin test?

The Mantoux tuberculin skin test (TST) is the standard method of determining whether a person is infected with Mycobacterium tuberculosis (TB).

How is the TST Administered?

The TST is performed by injecting 0.1 ml of tuberculin purified protein derivative (PPD) into the inner surface of the forearm. The injection should be made with a tuberculin syringe, with the needle bevel facing upward. The TST is an intradermal injection. When placed correctly, the injection should produce a pale elevation of the skin (a wheal).

How is the TST Read?

The skin test must be evaluated (or read) by a member of our nursing staff. The skin test reaction must be read between 48 and 72 hours after administration. A patient who does not return within 72 hours to be read will need to be rescheduled to have another skin test administered.