Hi Lake Lover,
I have the same problem and don't secrete TSH. It's actually a pretty common problem after permanent treatment for hyperthyroidism. Fortunately for me, my doctor looks at my FT4 and FT3 levels. Some endos understand this and don't even order TSH levels on Graves' patients on replacement therapy. You could ask for a bone density scan to see if the concern over bone loss is legitimate.
A TRH test could also be helpful for showing if patients like us produce TSH in response to thyroid-releasing-hormone stimulation. Before Brokken's reports showed the antibody connection causing a low TSH, other researchers noted that patients on full replacement hormone often have an intact pituitary-hypothalamic-thyroid axis. this just means that the brain is smart enough to realize we no longer produce thyroid hormone and don't have a need to make TSH. Ordinarily, if thyroid hormone levels are low, the hypothalamus secretes TRH and this causes us to produce TSH. there's a question as to whether we stop producing TRH or no longer respond to it. I'm not sure if this has ever been researched but if it has, such studies could also be used to show why we're not secreting TSH. A TRH would be more helpful academically than for us since it could potentially raise our thyroid hormone levels. In this test, TRH is administered and TSH levels are tested before and twice after the administration to see if there's an increase in TSH. I'll try to find out if there are any studies on this that could help with interpreting our test results. Best, Elaine