Hi Margiepenny,
the TSH is not an important result in your case as you have already been on thyroid meds for 35 years. In cases like yours when a person is medicated the TSH will typically be falsely suppressed. I have been on thyroid meds for 16 years now and my TSH is also very very low. But I am not overmedicated.
The important tests will be FT3 and FT4, which reflect your actual available thyroid hormone.
Please get these tests done. Ideally both will be in mid or upper 1/2 of the ranges given.
Also important is how you feel, whether you have decent energy etc.
I had my thyroid removed in 1980...I take.2 .2 Synthroid per day. My recent TSH was 0.006. What do I need to do?
The T3 and T4 are not too high, the low TSH is not necessarily a problem if she has no symptoms.
Doctor needs FT3 and FT4 next time, which will give the level of active thyroid hormones. Testing of antibodies need to be done too.
But more testing may be required.