If you had BCG vaccination in the past, your PPD is going to be positive. Then you need chest x-ray. If CXR normal or only calcifications, then you are set, do not need to take anti-TB medications, unless you want to. If CXR positive, you have to take medications 3 to 6 months depending on the regime.
This is a common problem concerning most Chinese in our daily practice. There is specific recommendations by CDC. Please print out a copy of the CDC recommendation and have it handy as not every one, even physicians, is square about this.
Good luck!!!