Final answer:
A positive TB skin test indicates exposure to the TB bacteria; however, not all individuals with a positive result require isolation. Further tests such as chest radiographs are needed to confirm an active infection and decide on isolation.
Step-by-step explanation:
If a person has a positive skin test for TB, it does not automatically mean they should be put in isolation. A positive Mantoux tuberculin skin test indicates that the person has been exposed to the bacteria Mycobacterium tuberculosis and exhibits a cellular immune response. This could be due to a current active TB infection, a past infection that has been cleared, or a latent TB infection. Furthermore, individuals who have received the BCG vaccine, which is not used in the United States, may show false-positive results because the vaccine prompts an immune response that is detected by the test. To determine whether the person has an active TB infection, further tests such as chest radiographs are required. If these additional tests indicate active TB, then isolation and medical treatment may be necessary to prevent the spread of the disease. It is important to note that a positive skin test on its own does not confirm an active infection, and not every person with a positive result will be contagious and require isolation.