Test Overview
A tuberculin skin test is done to see if you have ever had
tuberculosis (TB) (Mycobacterium
tuberculosis). It is done by putting a small amount of TB protein (antigens) under the top layer of skin on your inner
forearm. If you have ever been exposed to the TB bacteria, your skin will react
to the antigens by developing a firm red bump at the site within 2 days.
The Mantoux skin test uses TB antigens called purified protein
derivative (PPD). The test cannot tell if the infection is active or inactive
(latent).
The Mantoux test uses a measured amount of PPD in a shot that is
put under the top layer of skin on your forearm. A Mantoux test is a good test
for a TB infection. It is often used when symptoms, screening, or testing, such
as a chest
X-ray, show that a person may have TB.
A tuberculin skin test cannot tell how long you have been infected
with TB or if the infection can be passed to others (active TB).