DiagnosisThe diagnosis of TB is made on the basis of laboratory test results. The standard test for is the so called tuberculin skin test the presence of infection, not of active TB. Tuberculin is an extract prepared from cultures of M. . It contains substances belonging to the bacillus (antigens) to which an infected person has been sensitized. When tuberculin is injected into the skin of an infected person, the area around the injection becomes hard, swollen, and red within one to three days. Today skin tests utilize a substance called purified protein derivative (PPD) that has a standard chemical composition and is therefore is a good measure of the presence of tubercular infection. The PPD test is also called the Mantoux test. The Mantoux PPD skin test is not, however, 100% accurate; it can produce false positive as well as false negative results. What these terms mean is that some people who have a skin reaction are not infected (false positive) and that some who do not react are in fact infected (false negative). The PPD test is, however, useful as a screener. Anyone who has suspicious findings on a chest x ray, or any burberry condition that makes TB more likely should have a PPD test. In addition, those in close contact with a TB patient and persons who come burberry from a country where TB is common also should be tested, as should all healthcare personnel and those living in crowded conditions or institutions. Honestly, are burberry you that dense? Companies still make T Bird parts for many times what they once sold for try getting one from Ford for free, tell me how that turns out for burberry burberry you. Likewise, if you pay the $250 for MS support they'll often write little barely tested patches to fix your particular bug.