What does a positve tb screening look like?

a test you take to see if you have tuberculosis
Answer:
A TB skin test (also known as PPD) is a small intradermal injection (into the superficial layer of skin) containing antigens of the bacteria Mycobacterium Tuberculosis. If someone has a history of exposure to TB, his body will form antibody which will circulate around. Any further exposure to that bacteria or the antigen on the bacteria will cause activation of the immune system. When a skin test is placed, when someone has a history of exposure, body will form immune reaction around that part of skin, forming redess. The size of the reaction will determine prior exposure:* If you have HIV or on chemotherapy, any reaction greater than 5 mm diameter is positive;* If you have prior immunization to TB, low immunity, or chronic disease, 10 mm diameter or greater is positive test;* If you are of normal health and normal history, greater than 15 mm is positive;Test has to be read about 48 hours from the time of placement of the PPD. It also has to be read by medical professionals to document the result. If you missed the reading, a repeat test too soon may risk you a false positive test (because your body has already been exposed to the TB antigen in the recent past already)

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redness

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