Thyroid Disorders Community
what is the difference between T3 uptake and freeT3
About This Community:

This patient support community is for discussions relating to thyroid issues, goiter, Graves disease, Hashimoto's Thyroiditis, Human Growth Hormone (HGH), hyperthyroid, hypothyroid, metabolism, parathyroid, pituitary gland, thyroiditis, and thyroid Stimulating Hormone (TSH).

Font Size:
A
A
A
Background:
Blank
Blank
Blank
Blank Blank

what is the difference between T3 uptake and freeT3

Could someone explain? Everytime I get my blood taken they test free T4 and T3 uptake and TSH but not free T3 and after reading some here it sounds like I should be testing free T3 also.
Related Discussions
153 Comments Post a Comment
Blank
Avatar_f_tn
T3 uptake is a measurement of the protein that binds T3.  It is not a thyroid test, per se.

You're right, you want FT3.  FT3 and FT4 are the actual thyroid hormones.  Why do doctors insist on testing substances that are nort directly thyroid hormones?  Are they just as confused as we are?

Ask for FT3...you're paying for it!!!
Blank
Avatar_f_tn
I'm sorry, I didn't explain FT3 adequately.  FT3 is the T3 that is available to your cells. It is not bound by protein, and therefore inactive.  It is the most important indicator of your thyroid status.  Finding the FT3 at which YOU are confortable is the key to feeling well.
Blank
Avatar_f_tn
Thank you very much! I will ask for Ft3 next time. My doctor only looks at tsh though. How do I get him to look at the others? I just changed from synthroid and cytomel to Armour at my insistance because my tsh was .35 and still I have symptoms. I have been on Armour a week and can not tell much difference. I feel like I am doomed to always feel this way!
Blank
Avatar_f_tn
Well, if he's a TSH-only kind of guy, you're going to have to try to educate him.  If he's not receptive, you may have to find a new doctor.

Give your meds change more time to work...a week isn't time enough...it can take up to six weeks to really kick in.

You're not doomed to always feel crappy.  But you have to find a doctor who looks at your FT3 and FT4.  Using TSH only is just slightly better than guessing.
Blank
393685_tn?1325870933
I read your question and I am confused. You were on Synthroid and Cytomel. Cytomel is a T3 drug.

Why did you want to switch? Why did your doctor allow that switch without testing you appropriately using the Ft3 and Ft4 and trying to just tweak your meds?

Switching thyroid meds is difficult and now being on Armour - it may take you quite a while to stabilize on it. Without correct testing - it's a guessing game on where you may need to tweak your meds.

Same rule would apply if you chose to tweak your Synthroid and Cytomel with proper labs instead of completely switching.

Let us know how you do. It may be helpful to take a peek at the health pages/ Armour here on this forum to follow the right way to stay on this med, now that you are on it.  
Blank
Avatar_f_tn
Sometimes HYPO symptoms can be just the opposite and to have your TSH at .35, I would be watching you dont go extremely hyper especailly with changing to Armour where the amount of T3 is not specifically as controlled as Cytomel.
Sometimes I have had 'crossover' symptoms where I feel cold (Hypo) and yet have a fast heart rate (Hyper) ...only to find that I am hypo.
Get your Free T3 done as I feel you may be just a tad hyper.
Gut feeling I have.
Blank
Avatar_f_tn
Thank you all for your help. My doctor tests my tsh, free t4 and t3 uptake. I went to a specialist and he is the one that put me on Cytomel about a year and a half ago. I could not tell any difference. I did not like the specialist and went back to my regular MD for follow-up. After this long on Cytomel with out any improvement I asked to change to Armour. He said it would be like starting all over again to get meds right. I said I did not care because I am as far as I can go with Synthroid and Cytomel and still having symptoms. I was on 112mg of Synthroid and 5mg of Cytomel and now I am on 120 mg of Armour. That was my starting dose. I have not really had any side effects (except constipation but had that on and off before) but don't feel any better either. I did read on here that you should start slow and work your way up but my doctor did not do that. So I don't know . I go back in about three weeks for blood tests. I am going to ask for the free t3 also.
Blank
Avatar_f_tn
How are you doing?
I was on Synthroid 137 and cytomel and my T3 still stayed at 60. My Endo said I did not have any T3. She put me on Armour 180 to start. I felt better in 2 days. Loved that stuff! Then they changed to compound. Now I am in trouble again. My body uses the natural better than the synthroid. My T3 went to normal on the Armour. I am thinking about changing to another natural. Waiting for the Dr. to call me back. My THS was a little off last time so the Doc increased me to 210 on the Armour. We wiil see what he decides.
Blank
Avatar_f_tn
I am not seeing much improvement so far but I don't think the dose is right. I hope it will get better soon!
Blank
Post a Comment
To
Blank
Weight Tracker
Weight Tracker
Start Tracking Now
Thyroid Disorders Community Resources
RSS Expert Activity
469720_tn?1388149949
Blank
Abdominal Aortic Aneurysm-treatable... Blank
Oct 04 by Lee Kirksey, MDBlank
242532_tn?1269553979
Blank
The 3 Essentials to Ending Emotiona...
Sep 18 by Roger Gould, M.D.Blank
242532_tn?1269553979
Blank
Control Emotional Eating with this ...
Sep 04 by Roger Gould, M.D.Blank
Top Thyroid Answerers
649848_tn?1357751184
Blank
Barb135
FL
168348_tn?1379360675
Blank
ChitChatNine
Avatar_f_tn
Blank
goolarra
Sisters, OR
Avatar_m_tn
Blank
gimel
MI
657231_tn?1390151580
Blank
rumpled
Northern, NJ
Avatar_m_tn
Blank
flyingfool
WI