Tuberculin Skin Test (TST)
Procedure (Note -This synopsis is intended to provide a basic understanding of the TST procedure; to provide greater detail is beyond the scope of this course.)
1. The standard TST is performed using the Mantoux technique, where 0.1 mL of 5 tuberculin units of tuberculin purified protein derivative (PPD) is injected intradermally (into the top layers of skin) on the forearm (also known as the volar surface) using a 27-gauge needle and a tuberculin syringe.
2. Trained providers read the skin test after 48–72 hours.
3. The presence or absence and the diameter of induration (hard bump) are measured in millimeters.
