[header] How to read a tuberculosis skin test [title] Go to your doctor for the tuberculosis skin test. [step] You will be given an injection of a purified protein derivative into the inner forearm that will result in a 6-10 mm welt that will disappear within a few hours. [title] Leave your arm uncovered. 
[step] Do not place a bandage over the site of the test for the required 48 to 72 hours. You can wash and dry your arm carefully.