I have just found out that my 28 year old daughter was diagnosed with an underactive thyroid in 2010 and no-one told us. I am trying to find information about it but we have to wait 2 weeks for an appointment at the doctor's. All I know is that the brain blood test was positive and the other one was negative. I am very confused as I thought that once you had it you always had it. Can you tell me where I can get some information about it please? I am also thinking of making a complaint as we were never told she had it in the first place. We have to wait 2 weeks for a doctors appointment and 2 more weeks for blood tests. Hope you can help.