How soon can you take a tb test after being exposed to someone who has it?

TB: TB screening is recommended if you have been in close contact with a person with active TB in their lungs. If exposed in the last 8 weeks, the initial test may not be positive as your body may not have mounted an appropriate response to the exposure yet. Testing should be repeated at 3 and 6 months. A positive test should be followed by a chest x-ray and in depth discussion with your PCP.