Proportion of serum thyroid hormone concentrati... - Thyroid UK

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Proportion of serum thyroid hormone concentrations within the reference ranges in athyreotic patients on levothyroxine monotherapy

helvella profile image

A Japanese paper which suggests measuring FT3 might be more useful than FT4.

I've only read the abstract so far - but will read the full paper later.

Thyroid Res. 2022 May 10;15(1):9.

doi: 10.1186/s13044-022-00127-3.

Proportion of serum thyroid hormone concentrations within the reference ranges in athyreotic patients on levothyroxine monotherapy: a retrospective study

Mitsuru Ito 1 , Sawako Takahashi 2 , Mikiko Okazaki-Hada 2 , Mizuho Minakata 2 , Kazuyoshi Kohsaka 2 , Tomohiko Nakamura 2 , Toshihiko Kasahara 2 , Takumi Kudo 2 , Eijun Nishihara 2 , Shuji Fukata 2 , Mitsushige Nishikawa 2 , Takashi Akamiuzu 2 , Akira Miyauchi 2


• PMID: 35534833

• DOI: 10.1186/s13044-022-00127-3


Background: In patients receiving thyroid-stimulating hormone (TSH) suppressive therapy with levothyroxine (LT4) after total thyroidectomy for thyroid cancer, thyroid function tests should be performed to adjust the LT4 dose. Specifically, serum TSH concentrations are commonly measured because TSH suppression is necessary according to thyroid cancer risk. The aim of the present study was to elucidate whether free thyroxine (FT4) or free triiodothyronine (FT3) indicates better for adjusting the dose in athyreotic patients on LT4 monotherapy after total thyroidectomy.

Methods: We retrospectively studied the compatibility of free thyroid hormone (FT4 and FT3) concentrations with reference ranges in athyreotic patients on LT4 monotherapy after total thyroidectomy.

Results: We identified 2210 consecutive patients from their medical records. Of these patients, 250 had both FT4 and FT3 concentrations in addition to TSH. Two hundred seven had serum TSH concentrations below the reference range (0.5-5.0 μIU/mL), while 43 had them within the reference range. In the 207 patients with TSH concentrations below the reference range, 61 patients (29.5%) had FT4 concentrations within the reference range (0.9-1.7 ng/dL) and 146 patients (70.5%) had FT4 concentrations above the reference range. In contrast, 10 patients (4.8%) had FT3 concentrations below the reference range (2.3-4.0 pg/mL) and 8 (3.9%) had FT3 concentrations above the reference range; 189 patients (91.3%) had concentrations within the reference range. Of the 43 patients with TSH concentrations within the reference range, 25 (58.1%) had FT4 concentrations within the reference range and 18 (41.9%) had FT4 concentrations above the reference range. While, 11 patients (25.6%) had FT3 concentrations below the reference range and one (2.3%) had FT3 concentrations above the reference range; hence, 31 patients (72.1%) had FT3 concentrations within the reference range.

Conclusion: This study showed that measuring FT3 concentrations rather than FT4 concentrations as the subsequent parameter of thyroid function might be more useful for disease management in terms of the proportion of serum thyroid hormone concentrations within the reference ranges. Furthermore, FT3 measurement could be useful in providing more detailed treatments, including avoiding more aggressive TSH suppressive therapy and identifying the presence of low T3 syndrome in the background.

Keywords: Athyreotic patients; Thyroid-stimulating hormone suppressive therapy; Thyroxine; Triiodothyronine.

Full paper freely accessible here:


40 Replies

That makes more sense than just doing TSH or FT4. Thanks for posting this helvella. Let's hope that the 'powers that be' pay attention to this.

This is a joke!

Don't they know that T3 is the active thyroid hormone etc etc etc.

Or are they trying to use this study to force change

Just a monumental disgrace that the decision makers don't understand this.

If they did, many patients would have an improved QOL

This lack of medical knowledge about T3 almost cost me my life.

TUK enabled me to read and learn.

Thank you TUK!

I wonder if they will look down from "thyroid towers" on us lowly patients, read this, have a lightbulb moment and think....

We need to change our protocols

That would be a miracle....long overdue!

Sorry, this has been a challenging day ( non thyroid)

Hence my " rattled" response.

T3 is my hobby horse!!

If this reaches the right people....then well done those researchers.

Confession....but, I still have to read the full paper!!

Mamapea1 profile image
Mamapea1 in reply to DippyDame

Don't apologise DD...I agree with your reply entirely, and I haven't had a challenging day!😊 I also nearly lost my life because of the ridiculous medical gaslighting about T3, and when people nearly kill you, it tends to make you a bit annoyed!

Like you, I got away with my life because of this forum, but they still took a huge chunk of it, and the effects of my numerous disabilities had a profound effect on my family and finances...I missed out on what should've been the best years, and it's hard not to feel bitter about it at times 😔

And I dare say my death certificate would not have said 'a lack of T3' but that's basically what it would've been after all those years. They would have had lots of other diagnosed 'conditions' to choose from. It really is ridiculous.

I'm so grateful to everyone here who generously gave their time to put me on the right track and literally save my life. It's beyond words how I feel about it, but it's also a worry for all the poor souls who don't find this forum, and continue to suffer, as the medical dogma continues unabated.

I must admit, when I was scrolling through posts and read the first line...'A Japanese paper which suggests measuring FT3 might be more useful than measuring FT4' I laughed out loud...perhaps with a slight note of hysteria, although I dislike that word 😂

That's because those of us who have been dragged through the TSH/T4 mill, been told results are 'fine', diagnosed with ME/CFS/FM, anxiety and depression, rheumatism, IBS, allergies, asthma, COPD, essential tremors, even insanity and malingering are SO sick of it! 😒

I wish the paper every success in getting the word out, and it's mildly encouraging, but I'm not holding my breath. I feel the forum still has its work cut out for now. There are so many studies re T3, yet no action, that it's now becoming a sick joke, sadly 😕

DippyDame profile image
DippyDame in reply to Mamapea1

Thank you for your support Mamapea1

I was saying to my husband only yesterday that without this forum I would have felt as if I was the only one in this situation.It has helped me keep my head above water ( literally!)

We may be damaged by this scandal...but we live to fight on!

Take good care.

Mamapea1 profile image
Mamapea1 in reply to DippyDame

Absolutely! And you take care too 🌻

TSH110 profile image
TSH110 in reply to Mamapea1


TaraJR profile image
TaraJR in reply to DippyDame

DippyDame it could've been me writing that. Every word - the same experience and feelings as me!!

TSH110 profile image
TSH110 in reply to DippyDame

You’re spot on - the pure ignorance from supposed experts is exasperating not even a basic grasp on the fundamentals….sigh

shaws profile image

Yes, it makes sense and it is a pity that doctors and endos seem to be completely unaware that FT3 is the active thyroid hormone that runs our whole body, brain and heart having the most T3 receptor cells.

I think the professionals only take notice of a T4 result and are completely ignorant about anything to do with hypothyroidism or how to relieve clinical symptoms that some people cannot relieve.

TSH110 profile image
TSH110 in reply to shaws

Their ignorance is legion

A really interesting study Helvella. Thank you.

Having read it (more than once lol) it saddens me to see the reliance on tsh. It may be looking towards looking at levels more but is it me or is it so that suppression of tsh can be avoided? They never seem to address an impaired pituitary response to tsh and levels. I am sure many members can relate to that one.

Obviously I’m not a scientist but again I didn’t feel this was thorough enough. The mention of underlying health conditions without clarifying what these were, referencing previous research on tsh suppression but indicating it wasn’t definitive in its conclusion, etc … frustrating. However I know all research can only be beneficial and I also know we all want the paper that says tsh is a red herring, ft4 and ft3 are the only hormones that matter with reference ranges that start higher than they are now 🤞🏻🤞🏻🤞🏻Onwards and upwards.

helvella profile image
helvellaAdministrator in reply to Yeswithasmile

I think this statement in the Discussion says a lot:

First, in this retrospective study, only patients who underwent both FT 4 and FT 3 measurements were included, while patients who underwent either FT 4 or FT 3 measurement because the simultaneous measurement of FT 4 and FT 3 would not be approved for insurance reimbursement were excluded.

The short-sightedness of both the Japanese insurance companies and our NHS (and many other countries/systems) which considers only whether they can get away without paying for FT4 and FT3 tests regardless the consequences. Many on this TUK forum have seen all too many who might well have ended up cheaper to manage by proper testing rather than scrimping on testing and paying out for goodness knows what additional investigations and treatments.

Yes. Exactly. I couldn’t agree more.

But money makes the world go round. It’s so backwards. You would of thought a ‘think tank’ would have realised this by now lol.

DippyDame profile image
DippyDame in reply to helvella

Certainly in my case the NHS could have saved a considerable amount of money by getting to the root of my thyroid condition rather than, for decades, "paying out for goodness knows what additional investigations and treatments."

They could also have saved me a lot of money... paid for numerous alternative private treatments!

Money that I ( and many like me) still have to pay out to buy T3 so that I can self medicate with the supraphysiological dose I need to function!

The endo said I should continue with levothyroxine....which after 20 years left me barely able to function.

Instead, several ThyroidUK members supported me as I worked to find the answers that I was convinced existed.

Thank you TUK experts....always!

You all know who you are.

The NHS could have spared me decades of poor health and lost opportunities both personal and professional.

Please don't read this as a "sob story". I've been fortunate to have a supportive and understanding family....but I'm sure many others have fared far worse and will continue to do so.

It is unforgivable...

The result of misplaced penny pinching and medical failure.

Until the (life saving) importance of T3 is understood and the " bean counters" recognise their priorities and know how to balance the books, patients will continue to suffer.

But nothing will change so long as cries for change continue to fall on deaf ears.

As we know, that has been valiantly attempted in both Westminster and Holyrood!

Any positives this paper offers are likely to end similarly.

helvella profile image
helvellaAdministrator in reply to DippyDame

We often see that healthcare/human body research finds things that do not work as we might expect. That is, there are (apparent) paradoxes.

For example, the slightly odd happenings in the hunting reaction (or reflex) where there is a pattern of vasoconstriction alternating with short periods of increased blood flow after immersion in cold water. But, contrary to expectation, cold acclimation ends up reducing the hunting reaction and makes our extremities more likely to be damaged by cold exposure.

Primary school thinking about thyroid would look at T3, having been demonstrated to be the active hormone, as the obvious thing to measure. But it was always possible that some seemingly paradoxical effect meant that wasn't so.

Healthcare seems to have decided that T3 levels simply vary too much. Therefore they should be more or less totally ignored. Yet T3 is more stable than has been claimed. And they really have not demonstrated a paradoxical effect which would imply TSH and/or FT4 a better thing to measure.

The one real problem area I see is low T3 syndrome in illness. They need to recognise this and understand the optimum way of handling the situation.

Zazbag profile image
Zazbag in reply to helvella

It’s like they want to pretend thyroid disease management is simple and easy by dismissing the importance of T3, because that would actually require input, knowledge and more consistent monitoring and is therefore an expensive inconvenience. If it was diabetes where the risks of poor treatment were more obvious then we might be taken more seriously, but we suffer invisibly and are easy to ignore when hypothyroid because we just don’t have the strength to fight. It’s criminal.

jade_s profile image
jade_s in reply to helvella

I never understood the 't3 levels are unstable' line of thinking. My levels hardly budge if i get tested 1st thing in the morning, fasting and no meds, and X hours after last dose of T3. Maybe they mean that everybody metabolizes it different so the washout period is longer in some than others, or the same dose increases levels differently, but that doesn't mean it 'fluctuates' or varies too much in a single person 🤷‍♀️ . btw I haven't read the article yet!

In Belgium they refuse to run FT3 if TSH & FT4 are both in range. They = the labs don't run it because insurance won't cover it, and there's no way to get them to run it and just pay out of pocket. Luckily my TSH is currently suppressed so they run it, but at some point I had to go to france to get private labs to get a FT3 reading. Totally ridiculous they don't test it in many countries (probably due to the above argument).

And it seems to me that FT3 has become standard only recently. Well 'recently' in healthcare terms. About 15? years ago they were always running Total T3, T3 uptake etc in belgium. In the US they are still included in a standard panel though that's starting to change too.

helvella profile image
helvellaAdministrator in reply to jade_s

I never understood the 't3 levels are unstable' line of thinking.

You are being extremely generous to those who make that claim by suggesting it is the result of thinking. :-)

It is true, though, that T3 levels do respond to thyroid hormone dosing - whether T4, T3 or T4+T3. Typically, the maximum impact on T3 levels from taking T4 occur around 48 hours after ingestion.

But, if they need to take dosing in to account, then let them do so. (And, on a stable regime, it is surely simple enough to allow for?) Rather than wearing blinkers and ignoring the primacy of T3 as the active compound.

jade_s profile image
jade_s in reply to helvella

You are being extremely generous to those who make that claim by suggesting it is the result of thinking. :-)


True, true.

It would explain a lot!

Anyway, agreed.

DippyDame profile image
DippyDame in reply to helvella

Low cellular T3 is also a " real problem area".As is Thyroid Hormone Resistance.

T3 scares them because they don't bother to thoroughly understand it

It might affect a few people...

It's not visible ...

so, just not worth the effort.


helvella profile image
helvellaAdministrator in reply to DippyDame

Yet we see bold claims of amazing work done on rare diseases - some of which only affect a handful of people on the planet. Sure, some of the claims are really excellent news. Even if you are the only person with an issue, it is good to get treated better. But the claims are sometimes of the "aren't we wonderful" type.

DippyDame profile image
DippyDame in reply to helvella

...and some of those rare treatments cost an absolute fortune.Way beyond the cost of T3.

Maybe some are part of a research budget!

Happy to see others treated but a level playing field would be welcome

jade_s profile image
jade_s in reply to DippyDame

And importantly, what you said earlier but that I had missed : "They could also have saved me a lot of money... paid for numerous alternative private treatments!"

Exactly! How much money have we all spent/lost on expensive alternative/private docs, treatments, supplements, lost income, lost TIME, etc etc etc, all for a tiny tablet that costs peanuts to produce, and an FT3 test that probably doesn't cost all that much either. Such a travesty (is an understatement).

TSH110 profile image
TSH110 in reply to jade_s

Couldn’t agree more

TSH110 profile image
TSH110 in reply to DippyDame

It seems scandalous that huge numbers are kept ill when there’s no excuse for it.

shaws profile image
shawsAdministrator in reply to TSH110

The statement 'ignorance is bliss - doesn't apply to the many doctors who may diagnose a patient with hypothyroidism and it certainly does not include diagnosing by symptoms alone - as our 'old-fasthioned' doctors used to do before bood tests were introduced.

My GP phoned to state that my blood tests were fine and I had no problems. !!!! a TSH of 100 and he couldn't even understand a patient had undiagnosed hypo!!!!

jade_s profile image
jade_s in reply to shaws

My jaw still drops every time I read you say that. *100* and "you're fine"! I have no words 😱

TSH110 profile image
TSH110 in reply to shaws

It’s just terrible your GP did the Shaws like the tom fool I saw at the hospital who said I was euthyroid with a TSH of 80 😱how do these people get to practice medicine? Or rather not practice it

TSH110 profile image
TSH110 in reply to helvella

I agree

TSH110 profile image
TSH110 in reply to DippyDame

Yet it’s a fascinating hormone who couldn’t want to learnmore about it? Medics too 😱

TSH110 profile image
TSH110 in reply to DippyDame

Same here DD the number of completely unnecessary and expensive investigations I underwent & the useless drugs I ended up taking is a disgrace. All I needed was a full thyroid panel someone able to interpret it correctly then be given some NDT would have saved the exchequer a lot of money as it affected my ability to work too.

I don’t think it’s a sob story at all DippyDame. I think it’s a story that is all too common amongst us on here. Sadly. I wonder how many people misdiagnosed like me with fibro and me and to an extent hypermobility are continuing to cost the tax payer fortunes too.

TSH110 profile image
TSH110 in reply to helvella

Isn’t it because the patients had thyroid cancer and they aimed for suppressed TSH? Not sure if an FT3 equivalent exists is used. Two of my relatives went on suppressed TSH protocol because of thyroid cancer one is still going strong the cancer came back after 8 years with the other. Perhaps it’s not a sensible measure in that case either tho but at least it isn’t as bad as being starved of hormones. I agree it’s an oxymoron to say FT3 is the best measure but then to make TSH the one that’s actually being counted as most important and FT3 it’s slave 🙄

I bet it was really difficult trying to find enough patients who had TSH /fT4/ fT3 done at the same time . Of course ,if more places DID routinely do all three together, the cumulative 'evidence' on the GP 's screen would no doubt undermine their own arguments for 'TSH being a good indicator' very quickly indeed.

......what a shame it's so impossible for them to get the evidence they need to learn from ..... If only there was a place where thousands of thyroid patients had already coughed up their hard earned pennies to get their own TSH /fT4 /fT3 /TPOab done ....a place that kept over a decade of these results online , along with extremely detailed patient histories ....that interested researchers could go and look at ,..... so they could plainly see the information about fT3 and learn from it ......, and prove to themselves just how bleedin' obvious it is that you usually need to look at all three together to have a cat in hells chance of figuring out what is going on with anybody.......

Oh wait a minute ...?

shaws profile image
shawsAdministrator in reply to tattybogle

Even though my TSH was 100, GP phoned to tell me that there was nothing wrong with my blood tests!

What chance do people have when doctors are so very ignorant of a common autoimmune condition that our 'old-fashioned doctors' diagnosed without the need of blood tests but by clinical symptoms alone and prescribing a trial of NDTs.

DippyDame profile image
DippyDame in reply to tattybogle

You're absolutely right tatty the evidence is all spades!

Ah! But we are only patients, what could we possibly know about our own bodies and how could we possibly know anything about the diagnosis and treatment of thyroid disease.I reckon T3 terrifies them ....they fear that prescribing more than a few mcgs ( if they dare prescribe any at all) will cause them to have deaths on their hands and no licence to practice.

I once mentioned Gordon Skinner to an endo and he visibly recoiled.

We need a very wealthy benefactor and a TUK Foundation!

Perchance to dream!

shaws profile image
shawsAdministrator in reply to DippyDame

You are correct DippyDame about the attitudes of the 'supposed to be' professionals' as few - if any GPs - were trained upon clinical symptoms.

Dr Gordon Skinner and Dr Barry Peatfield .

Both were pursued as if they were criminals and appeared before the GMC several times for doing as they were taught as students, i.e. symptoms, symptoms, symptoms as I was fortunate to consult these two emminent doctors who could tell before the patient sat down that they had a problem with their thyroid gland.

The saddest part was when hypo patients undiagnosed or undertreated took their own lives (I know of 2).

£xcerpt re Dr Skinner:=

!Dr. Skinner was brilliant about the connection between ME/CFS and hypothyroidism. Years ago, he was one who saw the association between the condition of Myalgic Encephalopathy (which is also a term for Chronic Fatigue Syndrome) and hypothyroidism, in spite of so-called normal ranges. This was huge information and the same association was also seen by some thyroid patients around the turn of the century when they were moving over to natural desiccated thyroid (NDT) and doing so much better than they did on T4-only like Synthroid. Read about Chronic Fatigue Syndrome right on STTM.

Dr. Skinner was sadly challenged by the GMC. In June of 2005, Dr. Gordon Skinner, who was a private practitioner in the UK, was called before the General Medical Council to ascertain his “fitness to practice”. And why was he called before the board? Because of alleged “inappropriate clinical practice including maintaining medication for patients at dangerous levels and failures of communication with other medical practitioners.” I mentioned this in October 2006. i.e. Dr. Skinner dared to listen to thyroid patient symptoms over what is deemed “normal” labwork via the TSH. He also dared to use natural desiccated thyroid, aka porcine thyroid extract, to treat his patients until they saw the removal of symptoms. He began to receive restrictions in his ability to practice.

Dr. Skinner was now prohibited from seeing new patients unless they had been referred by a General Practitioner, and his decisions were to be reviewed by the GMC every six months for the next three years.

In 2007, I heard from Lyn Mynott, chair of Thyroid UK about Dr. Skinner being brought before the General Medical Council (GMC) because he dared to treat his patients with thyroid hormone when they have so-called “normal” blood lab test results. The GMC attempts to dictate what is “a good standard of practice and care” for patients and the “proper standards in medicine”. I spoke about this folly in the July 2007 blog post. His restrictions continued.

Dr. Skinner was appalled by the belief that a TSH up to 10 was normal.

The Royal College of Physicians and the Royal College of General Practitioners had implied by 2010 that patients should not received a diagnosis of hypothyroidism if their TSH was less than 10, and Skinner found it senseless. They had also stated that the thyroid extract called Armour was a bad medication (in spite of the fact that millions of us worldwide have had our lives change thanks to NDT).

DippyDame profile image
DippyDame in reply to shaws

I mentioned in another post this morning that I was speaking to my ( fairly new to me) GP this morning about my chronic UTI which I told him I was convinced was the result of long time low cellular T3.He didn't flinch, listened, asked how much T3 I take, didn't criticise when I said 100mcg, I explained why.

He said he knew nothing much about T3 and actually said he thought my self management ( UTI included) was good.

Will that make any difference?

Sadly, he has to work with his hands tied behind his back and with the knowledge his med training instilled in him.

Few are trained to listen to, and look at, their patients as Dr Skinner and Dr Peatfield would have been taught.

And if they dare to think/ work outside the NHS box...

they will remember what happened to those wonderful old doctors who did just that.

shaws profile image
shawsAdministrator in reply to DippyDame

Yes. you are right that our 'knowledgeable doctors' were persecuted and I assume there are other doctors who followed the 'older method' or use their brains - probably also lost their livelihoods or are forced to prescribe T4 only/

TSH110 profile image
TSH110 in reply to shaws

It’s shameful they were treated like that by the ‘establishment’

There are useless ones that should be struck off, peddling the TSH over 10 rubbish, they are the menaces to our health who should not be allowed anywhere near those with thyroid disorder, but they seem to get the plumb jobs all for zero understanding of the areas they profess to be expert in, when in reality they are killing people or making their lives a complete misery by their poor practice, acting upon their stupid notions as if they were facts set in stone not ideas based on faulty reason devoid of science and not evidence based at all.

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