What is a Mantoux test?

A mantoux test is a skin test that uses PPD (purified
protein derivative) to test if someone has ever been exposed to tuberculosis (TB). A PPD
sample is injected subdermally in the anterior  forearm, in 48 hours the person returns
to the provider to have the test read. If the area of induration is more than 5 mm
(measured) they are said to have a positive test result. Protocol for a positive PPD is
a chest x-ray. The chest x-ray will either confirm the presence of TB or it will be
unremarkable. Even if the chest x-ray is negative some health care providers prescribe
anti tubercle medications. (just to be on the safe side).Note that if a positive result
is noted this does NOT mean that the person has TB. What it does mean is that either the
person is allergic to the PPD or at some point in the past they have come into contact
with someone that had TB.