So, I did a test with a company to find out any food intolerances I found out that I had 23 things I was intolerant to including plants, but it also came up with an issue with my thyroid. Anyway I went to the GP to get tests on my thyroid the t3, tsh, t4 etc and she said she would be surprised if I had an issue with my thyroid because it was fine 2 years ago and my question is does thyroid issues take years to show up in the blood or like what does that mean? How does it being fine 2 years ago have anything to do with now?