Normal TSH but low FT4

[nved]

Hello, 31 years old, male

Back in 2012 I had a thyroid panel test which showed
TSH 4.91 T4 6.98μg/dL T3 1.22 ng/mL

March 2013
TSH 4.13 Free T4 0.99ng/dL

August 2013
TSH 2.64
Free T4 0.70ng/dL ->LOW

I'm waiting for Anti-TG and Anti-TPO, mother and grandmother with hypothyroidism but why normal TSH and low T4?

[Otto44$]

will do. Thank you

[gimel]

Try this link.

http://informahealthcare.com/doi/abs/10.1080/13590840050043521

[gimel]

Yes, thanks for pointing out that I left out Free T3.  

You are very welcome.  Hope it works out well for you.

[Otto44$]

http://www.ingentaconnect.com/content/routledg/cjne/2000/00000010/00000002/art00002        

Was removed. Would you happen to have a copy to post in Medhelp?

[Otto44$]

I forgot to give you outstanding credit in your paper. You're such a great advocate as well as others that share their knowledge here. Keep up the great work!!

[Otto44$]

Thank you for sharing the above letter. I know I'll definitely be giving to my Dr. with a couple of minor changes. :)

Free T4 is below range, and my is likely low also.

Should this read, Free T4 is below range, and my Free T3 is likely low also?

[gimel]

Being an Endocrinologist does not guarantee a good thyroid doctor.  Many of them specialize in diabetes, not thyroid.  Also, many of them have the "Immaculate TSH Belief", like your doctor.  Others only want to use "Reference Range Endocrinology", by which they will tell you that a test that falls anywhere within the reference range is adequate for you.  Wrong, for the reasons I outlined in the letter.  You need a good thyroid doctor that will treat clinically, as described, or you will have to change your own doctor into a good thyroid doctor.  

[gimel]

Well, the GP is wrong.  So, if you want to try and influence him by giving him some scientific evidence, following is a form letter I wrote for several other members to try and give their doctors enough info to change their minds and treat out members clinically.  I have made a few changes to suit your situation, but perhaps you might want to make a few more tweaks to the letter, so you could use it with your doctor.  Also I would attach copies of the Attachments (links) listed in the letter.

Dear Dr. ___________

I am sending you this letter in hopes you will take time to read and prepare to discuss with me at next opportunity.  I am writing because I still suffer with numerous hypothyroid symptoms, even though my TSH is within the old range, but my Free T4 is below range, and my is likely low also.  I have spent considerable time searching and reading related information and discussing all of it with an experienced and knowledgeable friend.  I have learned  a great deal, which leads me here.

First, the "Immaculate TSH Belief' is a big problem for hypo patients.  Until this test was invented about 40 years ago, hypo patients were routinely treated clinically.   One of the many places this is discussed is in this interview with Dr. Derry, which you will find revealing.  

http://www.thyroid-info.com/articles/david-derry.htm               Att. 1.

Next is the assumption that TSH accurately reflects levels of the actual thyroid hormones.  In actuality, TSH cannot be shown to correlate well with either Free T3 or Free T4, much less with symptoms, which should be most important.   The following link is graphical presentation that shows the best correlation tof TSH to Free T4 and Free T3 I have ever found, and it is very clear that the correlation of TSH to Free T4 is poor, and even worse with Free T3.  

http://www.clinchem.org/content/55/7/1380/F2.expansion.html


In fact, scientific studies such as the following, have shown that hypo symptoms correlated best with Free T3, while Free T4 and TSH did not correlate at all.  

http://www.ingentaconnect.com/content/routledg/cjne/2000/00000010/00000002/art00002                         Att. 2

Next is that TSH becomes even less useful as a diagnostic by which to medicate a hypo patient when already taking thyroid meds.  This link from the British Medical Journal and quote confirm that position.

http://www.bmj.com/content/293/6550/808
"To establish their role in monitoring patients receiving thyroxine replacement biochemical tests of thyroid function were performed in 148 hypothyroid patients studied prospectively. Measurements of serum concentrations of total thyroxine, analogue free thyroxine, total triiodothyronine, analogue free triiodothyronine, and thyroid stimulating hormone, made with a sensitive immunoradiometric assay, did not, except in patients with gross abnormalities, distinguish euthyroid patients from those who were receiving inadequate or excessive replacement. These measurements are therefore of little, if any, value in monitoring patients receiving thyroxine replacement."

The next big issue is reference ranges.  Even though one of my Free T4 test results fell within the bottom end of the ranges, from my personal experience, and what I have learned, that clearly does not mean that is adequate to relieve symptoms.  The ranges are far too broad  because the ranges were erroneously established.   The ranges were established based on all patient data for which test results were available.  Then assumptions were made that about 2.5% of patients were hypothyroid and about 2.5 % were hyper, and reference range limits were established at those points.  About 10 years ago, the AACE finally acknowledged there are many, many more than 2.5 % hypo and hyper.  After purging the data base and recalculating the range limits, they made a huge change to the TSH range from .5 - 5.0, down to 3 - 3.0.  Unfortunately TSH is a poor diagnostic, as discussed above, so this change didn't help hypo patients very much.  Plus most labs and doctors continue to use the old range, even after 10 years.  The biggest impact from the acknowledgement that the TSH range was wrong, is that the ranges for Free T3 and Free T4 were established the same way as TSH.  Thus, it is extremely unfortunate that the ranges for Free T3 and Free T4 have never been corrected like done for TSH.  

If the data bases for Free T3 and Free T4 were purged of suspect patient test data, as done for TSH, the new ranges would be more like the upper half of the current ranges.    This clarifies why so many hypo patients with Free T3 and Free T4 in the low end of their ranges are still symptomatic.  There is some good info in this link.  Note the statement, "The Free T3 optimal range being above the midpoint is corroborated by three different sources.", and the references to scientific studies.  

http://tiredthyroid.com/optimal-labs.html        Att. 3

And if not convinced yet, here are the conclusions from a scientific study linked afterward.

"High individuality causes laboratory reference ranges to be insensitive to changes in test results that are significant for the individual.

The width of the individual 95% confidence intervals were approximately half that of the group for all variables.

Our data indicate that each individual had a unique thyroid function. The individual reference ranges for test results were narrow, compared with group reference ranges used to develop laboratory reference ranges. Accordingly, a test result within laboratory reference limits is not necessarily normal for an individual."

Andersen S, Pedersen KM, Bruun NH, Laurberg P. Narrow individual variations in serum T(4) and T(3) in normal subjects: a clue to the understanding of subclinical thyroid disease. J Clin Endocrinol Metab. 2002 Mar;87(3):1068-72.


So, if TSH and the existing reference ranges for Free T3 and Free T4 are inadequate to diagnose and treat hypo patients, what should be done.  From my position, clearly I think the best approach is clinical treatment.  During this search, I found a letter written by a thyroid doctor for patients that he sometimes consults with, after initial evaluation and testing.  The letter is then sent to the participating PCP of the patient to help guide treatment.  In the letter, please note this info.    "the ultimate criterion for dose adjustment must always be the clinical response of the patient. I have prescribed natural dessicated thyroid for your patient (Armour, Nature-Throid) because it contains both T4 and T3 (40mcg and 9mcg respectively per 60mg). This assures sufficient T3 levels and thyroid effects in the body. Since NDT has more T3 than the human thyroid gland produces, the well-replaced patient’s FT4 will be below the middle of its range, and the FT3 will be high “normal” or slightly high before the next AM dose."   This is a link to the doctors website.

http://hormonerestoration.com/files/ThyroidPMD.pdf              Att. 4.

I greatly appreciate your time and patience in taking up my concern.  I hope that I have given you enough evidence to reconsider my treatment.  I assure you that I have not just selected info, just to support my request.  I can provide references to more scientific extensive scientific evidence than you would ever want to read, along the same lines.  I hope this will persuade you to at least let me have a trial of increased thyroid meds, and then adjust Free T3 and Free T4 as necessary to relieve my hypo symptoms.  I look forward to a full discussion when I return for my next appointment.  

Sincerely,  


______________



Att. 1
Att. 2
Att. 3
Att. 4

[nved]

I will request an appointment with an endocrinologist and hopefully i will get therapy if needed!

[nved]

No test for Vitamin D i will request next time. I live in Greece. a General Practitioner said it's tsh that matters not T4!

[gimel]

It is difficult to find good thyroid doctors in the US.  Not being in the US, usually makes it even more difficult.   Where are you located?

Is your doctor willing to even prescribe some thyroid med, seeing that your Free T4 is below the range?  Beyond that, do you think you might be able to persuade your doctor to work with you and treat you clinically, if you provide enough scientific evidence?  I have lots of references to such info.  

B12 should be in the upper part of its range.  For men, ferritin should be 80 - 90.  What about Vitamin D?

[nved]

I'm not in the US, My B12 is borderline low and my ferritin is 42 (22-322)
i happen to suffer from ulcerative colitis!

[gimel]

Some typical hypothyroid symptoms.  Your limited test results, especially the Free T4, confirm low thyroid level.  Testing for TPO ab and TG ab will only confirm the possibility of Hashimoto's Thyroiditis, it won't change the apparent need to be put on thyroid replacement meds.

What you need right now is a good thyroid doctor.  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

If you will give us your location, perhaps a member can recommend a good thyroid doctor based on personal experience.  Whenever you see a doctor, I heartily recommend that you get tested for Free T3 and Free T4, along with TSH, Vitamin D, B12 and ferritin.  



.  

[nved]

Well depression, fatigue, intolerance to cold.
2012
TSH 4.91 (0.3-5.0) T3 1.22 (0.8-2.0) T4 6.98 (5.0-12.0)
March 2013
TSH 4.13 (0.27-4.20) Free T4 0.99 (0.93-1.70)
August 2013
TSH 2.64 (0.4-4.0) Free T4 0.70 (0.84-1.76)

[gimel]

Be aware that TSH is a pituitary hormone that is affected by so many variables that it is totally inadequate as the main diagnostic for thyroid issues.  Many doctors will tell you that TSH accurately reflects levels of the actual thyroid hormones, but in reality it cannot be shown to correlate well with either Free T3 or Free T4, which are the biologically active thyroid hormones, much less with symptoms, which should be the most important consideration.   The main value of TSH is to distinguish among primary, secondary or tertiary hypothyroidism.  

So, before going further, please post the reference ranges that go with the T4 and T3 test results, and also post whatever symptoms you are having.