The different lab tests are so confusing to me, but the reason I asked about
which test you had
is because I don't believe that the total T4 really tells you anything unless you also have the T3 uptake
test also. This is a section out of a book that I have:
Total Thyroxine (TT4) The TT4 test measures both bound and unbound T4 levels. (Remember
thyroid hormones travel through the bloodstream bound to proteins before they are released to
enter into cells, becoming unbound.) Therefore, it does not give you an idea of how active
T4 is, unless other markers are included, such as T3 uptake. T3 uptake indicates how much
thyroid hormone is entering cells. By measuring T4 along with T3 uptake, you can calculate
the activity of free T4. Total T4 can be altered by many drugs.
Functional range: 6-12 ug/d
Typical laboratory range: 5.4-11.5 ug/d
So I don't think that is the best test to show how your thyroid is functioning. There is a section about
recommended lab tests at the Stop the Thyroid Madness that you might want to look at before
your appointment with your endo:
http://www.stopthethyroidmadness.com/recommended-labwork/
You probably need to have the free T4 and free T3 tests and I would also make sure that you had
the Anti-Thyroglobulin and Anti-TPO to make sure you don't have Hashimoto's. Here is another
web site that describes more about thyroid tests:
http://www.ithyroid.com/thyroid_test_interpretation.htm
And one other site to check explaining thyroid tests:
http://thyroid.about.com/od/gettestedanddiagnosed/a/bloodtests.htm
I hope one of these will help.