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Hi guys, I'm new in here and I'd like to get some advise.

I've been struggling with different doctors and endocrinologists for years now and finally one decided to do all important thyroid hormone tests, after trying to convince they should try me on t3+t4 combination treatment and check for mineral, vitamin deficiency as well.

I'll be meeting that endo and discussing my results in the next few days.

I'd appreciate any info and advise I could get here about what information I should look for in those blood tests e.g. optimal hormone levels, all other important or related hormones, minerals and vitamins that are needed for me to feel well.

I believe she missed something so just in case I know what to ask for if that's the case.

7 Replies

Hi Gr8Nica and welcome to the forum.

The aim of a treated hypo patient generally is for TSH to be 1 or below or wherever it is needed for FT4 and FT3 to be in the upper part of their reference ranges, if that is where you feel well, when on Levo only.

Dr Toft, leading endocrinilogist and past president of the British Thyroid Association, states in Pulse Magazine, "The appropriate dose of levothyroxine is that which restores euthyroidism and serum TSH to the lower part of the reference range - 0.2-0.5mU/l.

In this case, free thyroxine is likely to be in the upper part of its reference range or even slightly elevated – 18-22pmol/l. Most patients will feel well in that circumstance.

But some need a higher dose of levothyroxine to suppress serum TSH and then the serum-free T4 concentration will be elevated at around 24-28pmol/l.

This 'exogenous subclinical hyperthyroidism' is not dangerous as long as serum T3 is unequivocally normal – that is, serum total around T3 1.7nmol/l (reference range 1.0-2.2nmol/l)."

To know if you are converting T4 to T3 well enough, then the free Ts should be in balance. If FT4 is high in range/over range and FT3 low in it's range, that is indicative of poor conversion. Another way to know is the FT4:FT3 ratio. Good conversion takes place when, upon being adequately treated with Levo (ie low TSH), the ratio is 4:1 or less. To find the ratio divide FT4 by FT3 eg

FT4 - 20 (12-22)

FT3 - 4 (3.1-6.8)

20 divided by 4 = 5:1 = poor conversion


For Vitamins and Minerals, the following levels are recommended for thyroid hormone to work properly

Vit D - 100-150nmol/L (the recommended level according to the Vit D Council)

B12 - An extract from the book, "Could it be B12?" by Sally M. Pacholok:

"We believe that the 'normal' serum B12 threshold needs to be raised from 200 pg/ml to at least 450 pg/ml because deficiencies begin to appear in the cerebrospinal fluid below 550".

"For brain and nervous system health and prevention of disease in older adults, serum B12 levels should be maintained near or above 1000 pg/ml."

Folate - at least half way through it's range

Ferritin - half way through it's range, with a minimum of 70 for thyroid hormone to work.

Bear in mind, this information is from patients who share their experiences and may not be the opinion of doctors unless backed by evidence from a reliable, reputable and acceptable source.


If you have any results, please post them with their reference ranges, for comment.


Great startating point for me and indication on how to challenge my endocrinologist.

That's a lot for that SeasideSusie.

I remember when I was showed results a few years back my TSH was very close to the end of range and FT4 somewhere closer to the lower range I think. However that might be not the case since a lot of time passed by. Ever since I was told my blood tests are within its range.

I'll post the current blood work once I get the results.


I meant thanks a lot 😊


Gr8Nica If you would like a copy of the Pulse article written by Dr Toft, then email louise.roberts@thyroiduk.org print it and highlight question 6 to show your doctor.


Thanks, I'll do that 👍


I believe Endocrinologists are told that to test TSH and T4 only is all the information they require, but we, the patients, have learned that a Full Thyroid Function Test is best, particularly if we've been having clinical symptoms. Tick off the ones below:-


FTFT - is TSH, T4, T3, Free T4, Free T3 and thyroid antibodies.

Your GP should test B12, Vit D, iron, ferritin and folate.

All blood tests for thyroid hormones should be at the earliest possible, and may not be possible if they draw blood at hospital. It should also be a fasting test (you can drink water) and if you were taking thyroid hormones you'd allow a gap of 24 hours between last dose and test and take afterwards.


Thanks shaws.

I'm not sure now if FTFT was requested, my memory doesn't always work when I need it to but I'm very sure FT3 was included this time as we were talking about issues with conversion from T4 to T3 and it was supposed to be included in the blood work. All and all I'll request it for sure if anything missing.


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