Quick Thyroid 101:
The thyroid produces two main hormones: T4 (thyroxine) and T3 (triiodothyronine). T4 is our storage hormone and is converted into T3, our active hormone. 20% of the conversion happens within the thyroid and the rest in various body areas (brain, pituitary, muscles,etc.).
TSH stands for thyroid stimulating hormone and is produced by the pituitary in response to the body's need for thyroid hormone (which fuels every single cell of the body). TSH is most responsive to the amount of T3 (active hormone) in the bloodstream.
An elevated TSH indicates an underactive thyroid - the pituitary is screaming at the thyroid to produce hormone. However, there are many, many things that affect TSH: infections, antibodies, pituitary dysfunction, etc. TSH can be skewed low because of these things and, therefore, it's not a reliable indicator of thyroid function.
Doctors get all caught up with the sensitivity of the test. Great, they can measure small amounts of TSH. That doesn't mean the test is a reliable indicator of thyroid function.
If you want the full skinny on proper hypothyroidism diagnosis and treatment, here's a good read:
www.thyroidscience.com/hypotheses/dommisse.feb.2008/dommisse.feb.2008.pdfAnd, if you scroll towards the bottom of the following link, you'll read about
the 300 different symptoms a person might experience ala hypothyroidism:
hypothyroidmom.com/300-hypothyroidism-symptoms-yes-really/For whatever it's worth, a healthy person has TSH 1.0 or lower. Since TSH can fluctuate as much as 200% over the course of a day, I don't have confidence that your TSH level indicates healthy thyroid function.
Thyroid-savvy doctors look at the actual levels of usable thyroid hormone to evaluate thyroid function: Free T4 (T4 or thyroxine, free direct) and Free T3 (tri-iodothyronine, free, serum).
Unfortunately, your doctor didn't run the right tests. You got an outdated thyroid profile.
The thyroxine test measures T4 that is bound to proteins and not usable by the body.
The T3 uptake test is an obsolete test in which T3 is used as a reagent in the test. This test measures how well your thyroid hormone binds to binding proteins. It's used to sort of estimate your Free T4 level when calculated with a T4 (thyroxine) result
And, you guessed it - the Free Thyroxine Index represents that calculation.
Why run all these lame tests that are trying to guesstimate your Free T4 level (and don't even measure your Free T3 level) when the actual tests are available to do so?
The fact that you tested negative for thyroglobulin antibody means you might not have autoimmune thyroid disease. You'd need TPOab (thyroid peroxidase antibody) and TSI (thyroid stimulating immunoglobulin) testing for complete autoimmune thyroid testing.
No matter what, even though you didn't list the range for your thyroxine result, I'm thinking the high end is probably 12. Your level is too low. If your body isn't producing enough hormone that's bound to proteins, it's a pretty sure bet you don't have much hormone available for your body's use.
Loss of the outer third of the eyebrows is a classic symptom of hypothyroidism. I hope you pursue Free T4 and Free T3 testing...and my offer for help remains :)