I had to get a TB test as part of my licensing to become a foster parent. I don’t know anything about TB so while I was with the doctor I asked some questions about why the health department requires TB tests. The doctor told me that it was protocol from decades ago that has just been rolled over and over. In his opinion though the test is pointless. What i discovered was that unless you are native to the US, a TB test will more than likely come back as positive. Outside of the US it is common for people to be vaccinated for TB. And if you have been vaccinated, that strain will always be present and kick out as a positive test.