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Thyroid Disorders Community
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Avatar universal

Thyroid results

Free T3   3.5             Range(3.1-6.8)
Free T4   15.84         Range(12.00-22.00)
TSH         0.46          Range(0.27-4.20) MIU/L

I do not know how the ranges work for T3 and T4, Could someone tell me?
6 Responses
Avatar universal
Well, unfortunately many doctors use the ranges as pass/fail decisions regarding whether to treat or not.  That really doesn't work because the ranges were improperly determined and are not functional for many patients.  The ranges should really be considered as guidelines within which to adjust Free T3 and Free T4 as necessary to relieve symptoms, since symptom relief is what is most important to us.  Many members here say that symptom relief required Free T3 in the upper third of its range and free T4 around the middle of its range.

A good thyroid doctor will treat a hypo patient clinically by testing and adjusting Free T3 and Free T4 as necessary to relieve symptoms, without being constrained by resultant TSH levels.  You can get some good insight into clinical treatment from this letter written by a good thyroid doctor for patients that he sometimes consults with after initial tests and evaluation.  The letter is then sent to the participating doctor of the patient to help guide treatment.  In the letter, please note the statement, "the ultimate
criterion for dose adjustment must always be the clinical response of the patient."

http://hormonerestoration.com/files/ThyroidPMD.pdf
Avatar universal
Hi Gimel,

  Thanks for the reply.
  I was wondering what in the world as so many others on here have completely different ranges than mine so I was having trouble understanding what my ranges mean.

  So, by what you are saying, my t3 is still in the low range. Does that low range indicate hyper or hypo? and my free t4 is in the low end of their ranges as well, does that mean Hyper or hypo? That's kind of where I am confused.  which end of the range is considered hyper? and which end of the range is considered Hypo?

   I'm concerned because before these results, I was in the hyper end while  I was  on 100 mcg of synthroid , and all of my ranges were coming back as over stimulated. So she lowered my dose to 75 and I am starting to feel normal again. So I was wondering if these results are okay or not.

Thanks again for your responses
Avatar universal
Generally speaking, for Free T3 and Free T4, low end of the ranges is tending toward hypo, and high end is tending toward hyper.  TSH is just the opposite.  Think of it somewhat like a see-saw with TSH on one end and FT3 and FT4 on the other end.  

You said you were hyper when on 100 mcg of Synthroid.  Was that based on how you were feeling, or the test results?  

Everyone is different and reacts to meds differently.  The key is how you feel, not test results.  
Avatar universal
Hi again,
  it was based on both test results and symptoms.

  My doctor is great, when I told her about all the information we were finding, she started testing all three as she found out that relying on TSH after starting therapy can become pointless. Her nurse forgot to print out the results then but I recall looking at the ranges while at the doctors office and they were completely opposite from these. the TSH was 0.07 and the free t3 and free t4 were very high over the range. but now, 8 weeks later what I have posted above is what they are on 75 MCG and the symptoms are mostly gone. except for the ones that could be from my deficiencies else wear.
Your information is very useful for me. Thanks again for responding!
Avatar universal
Since you have been fortunate enough to find a doctor that is willing to consider new information, you might also tell her that the ranges for Free T3 and Free T4 are just as flawed as TSH.  I say that because over 10 years ago the AACE admitted that the old range was incorrect because it was based on the total population of patient test data, including hypo and hyper patients.  They assumed that about 2.5% of patients had hypothyroidism and the same for hyper patients.  So they drew the upper and lower range limits accordingly.  When they finally decided to correct the range, they purged suspect hypo and hyper data and recalculated the range limits from .5 - 5.0 down to .3 - 3.0, which was a huge change.  

Unfortunately the ranges for Free T3 and Free T4 were established in the same manner and have never been revised similar to TSH.  The result is that test results in the low end of the range are frequently associated with having hypo symptoms.  This wouldn't really matter if doctors used the ranges as guidelines within which to treat hypo patients clinically, by testing and adjusting Free T3 and Free T4 as necessary to relieve symptoms.  Instead they use them as pass/fail decisions.  There is no logic to that.  Just think, if you are .01 below the range, are you hypothyroid and thus feel worse than if you were .01 higher and considered as "normal'?  For the Free T3 range, how can a patient at the very bottom of the range supposedly be just as well off as a patient that is at the high end of the range, which is 80% higher than the low end?

And even beyond the issue of what is a good result on a thyroid test, there is the issue of how that even relates to what is the most important, which is tissue thyroid levels.  Unless a patient's body "transports" the serum thyroid hormone adequately into the cells, tissue thyroid levels may be too low for symptom relief.  So far, the reported best measure of tissue thyroid levels is the ratio of Free T3 to Reverse T3, and many doctors don't even want to test for Reverse T3, even if there is a question that it might be an issue.

So, bottom line to me is that symptoms (how you feel) trump all else.  
Avatar universal
I absolutely agree with you there. Relief of symptoms is the trump all. I have this little thing where if I want something tested and the doctor sends me for blood work, yet some how ignored my request (the doctor I have now usually does what I ask) I check it off anyways. If there is some special routine I have to follow like fasting then I do it. ;-) She did mention running other tests including antibodies and some other things as I am suffering, but much of it is only when I have my monthly visitor. So WE are going through the motions of testing all of my hormones, since I suffer from PCOS and suspected endometriosis as well.

Thanks a ton for your feedback!
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