I am a female, 58 yo and have been on thyroid meds for 15 years. In Sept I was checked and my level was .5 and then in February I was checked and it was 20.0. My doctor upped my meds from 137 mcg to 200 mcg. I have moved to another state and will need to get a new doctor, but just today my older sister notified me that several years ago she had graves disease and had her thyroid irradiated. Could my low thryroid have gone to Graves disease? Nell Stranburg