Not to worry, they ran a piece on TB which demonstrated that the QFT marketing is really kicking in;
Mantoux skin test also known as a tuberculin skin test (TST): This test helps identify people infected with M. tuberculosis but who have no symptoms. A doctor must read the test.
The doctor will inject 5 units of purified protein derivative (PPD) into your skin. If a raised bump of more than 5 mm (0.2 in) appears at the site 48 hours later, the test may be positive.
This test can often indicate disease when there is none (false positive). Also, it can show no disease when you may in fact have TB (false negative).
QuantiFERON-TB Gold test: This is a blood test that is an aid in the diagnosis of TB. This test can help detect active and latent tuberculosis. The body responds to the presence of the tuberculosis bacteria. By special techniques, the patient's blood is incubated with proteins from TB bacteria.
If the bacteria is in the patient, the immune cells in the blood sample respond to these proteins with the production of a substance called interferon-gamma (IFN-gamma). This substance is detected by the test. If someone had a prior BCG vaccination (a vaccine against TB given in some countries but not the U.S.) and a positive skin test due to this, the QuantiFERON-TB Gold test will not detect any IFN-gamma.
