My mom had Grave's and thyroid surgery in the '60s and has been on synthroid ever since. I don't know the dosage. She recently had a TSH of 0.03 (0.3 - 3 range) and no other tests. She doesn't have high blood pressure or high cholesterol. She has a zometa infusion monthly for osteoporosis. She has breast cancer and is having chemo treatments at the present time. She only asked the oncologist for the TSH test because I insisted and doesn't plan to follow up with an endo. Should I be concerned? Your opinions will be greatly appreciated.