Fiance tested positive then negative for next two months on TB test. Why cant she get interview now?

I would get tested again because the skin test isn't always accurate.

Testing should at least be confirmed negative by two or more government approved testing facilities. Even if the test results after 2 months showed negative does not mean that the lungs are free from it. The disease is temporarily dormant until the body's immune system is at its low. When this happens, any bacteria or virus that has resided in our body may tend to resurrect. Cancer patients on remission is inclined to do likewise.