T4 Free and T3 Free

[bonniejean]

I recently had a TSH test (.003) My T4 (10.400) and T3 Uptake (27.1) were normal. My question is why would a doctor only want to take a T4 and not a T4 Free which is a much more affective measurement of tissue function. The T4 measures the total Thyroxine in the blood stream whereas a T4 Free would measure the affectiveness of the hormone that in the blood stream. Any thing anybody can add to this would be appreiciated.  Also I am worried if I should be concerned about having such a low TSH test.
Thanks Bonnie

[Jimlow]

Hi Bonniejean, that is a really low TSH, are you having any symptoms? Have they tested yout thyroid antibody levels?
Sincerely, JimLow

[bonniejean]

Any opinion or advice you might have would be greatly appreiated.
Thank You
Bonnie

[Mark Lupo, M.D.]

the low tsh demands checking t3 (not t3 uptake) as we need to determine how hyperthyroid you are - ie, subclinical or not.  If you are on any estrogens or are pregnant, the total t3 and t4 are falsely elevated - otherwise they are fine but I typically get free t4 and t3.  Antibodies would be interesting but not as important in this scenario.

[bonniejean]

I am not on any estrogen replacement, birth control, nor am I pregnant. I should also mention that I have severe joint pain. I had an MRI wed. and they found a rotor cuff tear in my left sholder.  It now feels like the same thing is happening to my right sholder and I can't help but think that this is somehow related to the hyperthyroidism. I have not injured either sholder. My sholders are my the most painful cause the pain goes down my arms and into my elbows and wrists. Nearly all my joints ache though but my sholders are the worse. I also have thickening of the skin on my calfs of my legs, a rash that Iv'e had for over a year. (Believe me I tried everything on it) Iv'e been to the doctor so many times and they only treated the rash.
Thank God I now Know what caused it and I'm not crazy.